diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fb9a056..7c68046 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -46,7 +46,7 @@ jobs:
         run: >-
           docker build
           -f ${{ matrix.dockerfile }}
-          --build-arg build_type=${{ matrix.build_type }}
+          --build-arg BUILD_TYPE=${{ matrix.build_type }}
           --target build
           -t ${{ matrix.image }}
           .
@@ -59,7 +59,7 @@ jobs:
           rm -rf dist
           docker build \
             -f ${{ matrix.dockerfile }} \
-            --build-arg build_type=${{ matrix.build_type }} \
+            --build-arg BUILD_TYPE=${{ matrix.build_type }} \
             --target export \
             --output dist \
             .
diff --git a/AGENTS.md b/AGENTS.md
index 10962ab..42600d5 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -6,7 +6,7 @@
 - Sample fixtures for exercising the loader live in `test/`.
 
 ## Build, Test, and Development Commands
-- `cmake -B build -GNinja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DBUILD_TESTING=ON` configures a 32-bit toolchain; ensure multilib packages are present.
+- `cmake -B build -GNinja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_EXPORT_COMPILE_COMMANDS=ON` configures a 32-bit toolchain; ensure multilib packages are present.
 - `cmake --build build --target wibo` compiles the program and tests.
 - `./build/wibo /path/to/program.exe` runs a Windows binary. Use `WIBO_DEBUG=1` (or `--debug`/`-D`) for verbose logging. Use `--chdir`/`-C` to set the working directory.
 - `cmake -B build -DBUILD_TESTING=ON` + `ctest --test-dir build --output-on-failure` runs the self-checking WinAPI fixtures (requires `i686-w64-mingw32-gcc` and `i686-w64-mingw32-windres`).
@@ -25,7 +25,7 @@
 - Add `DEBUG_LOG` calls to trace execution and parameter values; these are invaluable when diagnosing issues with real-world binaries.
 
 ## Testing Guidelines
-- Fixture tests live in `test/` and are compiled automatically with `i686-w64-mingw32-gcc` when `BUILD_TESTING` is enabled.
+- Fixture tests live in `test/` and are compiled automatically with `i686-w64-mingw32-gcc`.
 - Keep new repros small and self-contained (`test_<feature>.c`).
 - All fixtures must self-assert; use `test_assert.h` helpers so `ctest` fails on mismatched WinAPI behaviour.
 - Update `CMakeLists.txt` to add new fixture sources.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 681ac64..f95f2df 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,10 +1,5 @@
 cmake_minimum_required(VERSION 3.13)
 
-if(NOT CMAKE_BUILD_TYPE)
-    set(CMAKE_BUILD_TYPE "Debug" CACHE STRING
-        "Build type options: Debug Release RelWithDebInfo MinSizeRel" FORCE)
-endif()
-
 set(CMAKE_C_FLAGS_INIT "-m32")
 set(CMAKE_CXX_FLAGS_INIT "-m32")
 set(CMAKE_EXE_LINKER_FLAGS_INIT "-m32")
@@ -12,15 +7,35 @@ set(CMAKE_SHARED_LINKER_FLAGS_INIT "-m32")
 
 project(wibo LANGUAGES C CXX)
 
-list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+option(WIBO_ENABLE_FIXTURE_TESTS "Enable Win32 fixture tests (requires i686-w64-mingw32)" ON)
+option(WIBO_ENABLE_LIBURING "Enable liburing for asynchronous I/O" OFF)
+set(WIBO_ENABLE_LTO "AUTO" CACHE STRING "Enable link-time optimization (LTO)")
+set_property(CACHE WIBO_ENABLE_LTO PROPERTY STRINGS "AUTO" "ON" "OFF")
 
-set(CMAKE_C_STANDARD 11)
-set(CMAKE_CXX_STANDARD 20)
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -fno-pie -no-pie -D_LARGEFILE64_SOURCE")
+if (WIBO_ENABLE_LTO STREQUAL "AUTO")
+    if (CMAKE_BUILD_TYPE STREQUAL "Release" OR CMAKE_BUILD_TYPE STREQUAL "MinSizeRel")
+        include(CheckIPOSupported)
+        check_ipo_supported(RESULT ipo_supported OUTPUT ipo_error)
+        if (ipo_supported)
+            message(STATUS "Enabling LTO")
+            set(WIBO_ENABLE_LTO ON)
+        else()
+            message(STATUS "LTO not supported: ${ipo_error}")
+            set(WIBO_ENABLE_LTO OFF)
+        endif()
+    else()
+        message(STATUS "Disabling LTO")
+        set(WIBO_ENABLE_LTO OFF)
+    endif()
+elseif (NOT (WIBO_ENABLE_LTO STREQUAL "ON" OR WIBO_ENABLE_LTO STREQUAL "OFF"))
+    message(FATAL_ERROR "WIBO_ENABLE_LTO must be ON, OFF, or AUTO")
+endif()
+set(CMAKE_INTERPROCEDURAL_OPTIMIZATION ${WIBO_ENABLE_LTO})
 
-find_package(Filesystem REQUIRED)
-
-# Disable mimalloc tests
+# Fetch and configure mimalloc
+set(MI_BUILD_SHARED OFF CACHE BOOL "Build shared library" FORCE)
+set(MI_BUILD_STATIC OFF CACHE BOOL "Build static library" FORCE)
+set(MI_BUILD_OBJECT ON CACHE BOOL "Build object library" FORCE)
 set(MI_BUILD_TESTS OFF CACHE BOOL "Build test executables" FORCE)
 
 include(FetchContent)
@@ -31,35 +46,43 @@ FetchContent_Declare(
 )
 FetchContent_MakeAvailable(mimalloc)
 
-FetchContent_Declare(
-    liburing
-    GIT_REPOSITORY https://github.com/axboe/liburing.git
-    GIT_TAG        liburing-2.4
-)
-FetchContent_MakeAvailable(liburing)
+# Disable `note: the alignment of '_Atomic long long int' fields changed in GCC 11.1`
+target_compile_options(mimalloc-obj PRIVATE -Wno-psabi)
 
-set(LIBURING_COMPAT ${liburing_SOURCE_DIR}/src/include/liburing/compat.h)
-add_custom_command(
-  OUTPUT  ${LIBURING_COMPAT}
-  COMMAND ${CMAKE_COMMAND} -E env
-          CC=${CMAKE_C_COMPILER}
-          AR=${CMAKE_AR}
-          RANLIB=${CMAKE_RANLIB}
-          ./configure --cc=${CMAKE_C_COMPILER}
-  WORKING_DIRECTORY ${liburing_SOURCE_DIR}
-  COMMENT "Running liburing configure"
-  VERBATIM
-)
-add_custom_target(liburing_configure DEPENDS ${LIBURING_COMPAT})
-add_library(liburing STATIC
-  ${liburing_SOURCE_DIR}/src/queue.c
-  ${liburing_SOURCE_DIR}/src/register.c
-  ${liburing_SOURCE_DIR}/src/setup.c
-  ${liburing_SOURCE_DIR}/src/syscall.c
-  ${liburing_SOURCE_DIR}/src/version.c)
-add_dependencies(liburing liburing_configure)
-target_include_directories(liburing PUBLIC ${liburing_SOURCE_DIR}/src/include)
-target_compile_definitions(liburing PRIVATE _GNU_SOURCE)
+if (WIBO_ENABLE_LIBURING)
+    FetchContent_Declare(
+        liburing
+        GIT_REPOSITORY https://github.com/axboe/liburing.git
+        GIT_TAG        e907d6a342e80b70874f93abd440b92b8a40b7bc  # liburing-2.12
+    )
+    FetchContent_MakeAvailable(liburing)
+
+    add_custom_command(
+        OUTPUT  ${liburing_SOURCE_DIR}/config-host.h
+                ${liburing_SOURCE_DIR}/src/include/liburing/compat.h
+        COMMAND ${CMAKE_COMMAND} -E env
+                CC=${CMAKE_C_COMPILER}
+                CXX=${CMAKE_CXX_COMPILER}
+                ./configure --prefix=${liburing_BINARY_DIR}
+        WORKING_DIRECTORY ${liburing_SOURCE_DIR}
+        DEPENDS ${liburing_SOURCE_DIR}/configure
+        COMMENT "Running liburing configure"
+        VERBATIM
+    )
+    add_library(liburing STATIC
+        ${liburing_SOURCE_DIR}/config-host.h
+        ${liburing_SOURCE_DIR}/src/nolibc.c
+        ${liburing_SOURCE_DIR}/src/queue.c
+        ${liburing_SOURCE_DIR}/src/register.c
+        ${liburing_SOURCE_DIR}/src/setup.c
+        ${liburing_SOURCE_DIR}/src/syscall.c
+        ${liburing_SOURCE_DIR}/src/version.c
+        ${liburing_SOURCE_DIR}/src/include/liburing/compat.h)
+    target_compile_definitions(liburing PRIVATE _GNU_SOURCE _FILE_OFFSET_BITS=64 _TIME_BITS=64)
+    target_compile_options(liburing PRIVATE -include config-host.h)
+    target_include_directories(liburing PUBLIC ${liburing_SOURCE_DIR}/src/include)
+    target_include_directories(liburing PRIVATE ${liburing_SOURCE_DIR})
+endif()
 
 add_executable(wibo
     dll/advapi32.cpp
@@ -116,14 +139,24 @@ add_executable(wibo
     src/resources.cpp
     src/strutil.cpp
 )
-target_include_directories(wibo PRIVATE dll src)
+target_compile_definitions(wibo PRIVATE _GNU_SOURCE _FILE_OFFSET_BITS=64 _TIME_BITS=64)
 target_compile_features(wibo PRIVATE cxx_std_20)
-target_link_libraries(wibo PRIVATE std::filesystem mimalloc-static liburing)
+target_compile_options(wibo PRIVATE -Wall -Wextra -fno-pie -maccumulate-outgoing-args)
+target_include_directories(wibo PRIVATE dll src)
+target_link_libraries(wibo PRIVATE mimalloc-obj)
+target_link_options(wibo PRIVATE -no-pie)
+if (WIBO_ENABLE_LIBURING)
+    target_compile_definitions(wibo PRIVATE WIBO_ENABLE_LIBURING=1)
+    target_link_libraries(wibo PRIVATE liburing)
+    target_sources(wibo PRIVATE src/async_io_uring.cpp)
+else()
+    target_compile_definitions(wibo PRIVATE WIBO_ENABLE_LIBURING=0)
+endif()
 install(TARGETS wibo DESTINATION bin)
 
-include(CTest)
+if (WIBO_ENABLE_FIXTURE_TESTS)
+    include(CTest)
 
-if(BUILD_TESTING)
     find_program(WIBO_MINGW_CC i686-w64-mingw32-gcc)
     find_program(WIBO_MINGW_WINDRES i686-w64-mingw32-windres)
 
@@ -132,443 +165,105 @@ if(BUILD_TESTING)
         set(WIBO_HAVE_MINGW_TOOLCHAIN TRUE)
     endif()
 
-    option(WIBO_ENABLE_FIXTURE_TESTS "Build and run Windows fixture binaries through wibo" ${WIBO_HAVE_MINGW_TOOLCHAIN})
+    if(NOT WIBO_HAVE_MINGW_TOOLCHAIN)
+        message(WARNING "MinGW toolchain not found; skipping fixture tests")
+    else()
+        set(WIBO_TEST_BIN_DIR ${CMAKE_CURRENT_BINARY_DIR}/test)
+        file(MAKE_DIRECTORY ${WIBO_TEST_BIN_DIR})
 
-    if(WIBO_ENABLE_FIXTURE_TESTS)
-        if(NOT WIBO_HAVE_MINGW_TOOLCHAIN)
-            message(WARNING "MinGW toolchain not found; skipping fixture tests")
+        function(wibo_add_fixture_dll)
+            set(options)
+            set(oneValueArgs NAME)
+            set(multiValueArgs SOURCES COMPILE_OPTIONS DEPENDS)
+            cmake_parse_arguments(PARSE_ARGV 0 fixture "${options}" "${oneValueArgs}" "${multiValueArgs}")
+
+            set(fixture_OUTPUT ${WIBO_TEST_BIN_DIR}/${fixture_NAME}.dll)
+            add_custom_command(
+                OUTPUT ${fixture_OUTPUT}
+                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2 -shared
+                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
+                        -o ${fixture_OUTPUT}
+                        ${fixture_SOURCES}
+                        ${fixture_COMPILE_OPTIONS}
+                WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+                DEPENDS ${fixture_SOURCES} ${fixture_DEPENDS})
+            list(APPEND WIBO_TEST_FIXTURES ${fixture_OUTPUT})
+            set(WIBO_TEST_FIXTURES ${WIBO_TEST_FIXTURES} PARENT_SCOPE)
+        endfunction(wibo_add_fixture_dll)
+
+        function(wibo_add_fixture_bin)
+            set(options)
+            set(oneValueArgs NAME)
+            set(multiValueArgs SOURCES COMPILE_OPTIONS DEPENDS)
+            cmake_parse_arguments(PARSE_ARGV 0 fixture "${options}" "${oneValueArgs}" "${multiValueArgs}")
+
+            set(fixture_OUTPUT ${WIBO_TEST_BIN_DIR}/${fixture_NAME}.exe)
+            add_custom_command(
+                OUTPUT ${fixture_OUTPUT}
+                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
+                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
+                        -o ${fixture_OUTPUT}
+                        ${fixture_SOURCES}
+                        ${fixture_COMPILE_OPTIONS}
+                WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+                DEPENDS ${fixture_SOURCES} ${fixture_DEPENDS})
+            list(APPEND WIBO_TEST_FIXTURES ${fixture_OUTPUT})
+            set(WIBO_TEST_FIXTURES ${WIBO_TEST_FIXTURES} PARENT_SCOPE)
+
+            add_test(NAME wibo.${fixture_NAME}
+                COMMAND $<TARGET_FILE:wibo> ${fixture_OUTPUT})
+            set_tests_properties(wibo.${fixture_NAME} PROPERTIES
+                WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
+                DEPENDS wibo.build_fixtures)
+        endfunction(wibo_add_fixture_bin)
+
+        # Define fixture tests
+        wibo_add_fixture_bin(NAME test_external_dll SOURCES test/test_external_dll.c)
+        wibo_add_fixture_bin(NAME test_dll_attach_failure SOURCES test/test_dll_attach_failure.c)
+        wibo_add_fixture_bin(NAME test_thread_notifications SOURCES test/test_thread_notifications.c)
+        wibo_add_fixture_bin(NAME test_bcrypt SOURCES test/test_bcrypt.c COMPILE_OPTIONS -lbcrypt)
+        wibo_add_fixture_bin(NAME test_resources SOURCES test/test_resources.c ${WIBO_TEST_BIN_DIR}/test_resources_res.o COMPILE_OPTIONS -lversion)
+        wibo_add_fixture_bin(NAME test_threading SOURCES test/test_threading.c)
+        wibo_add_fixture_bin(NAME test_handleapi SOURCES test/test_handleapi.c)
+        wibo_add_fixture_bin(NAME test_findfile SOURCES test/test_findfile.c)
+        wibo_add_fixture_bin(NAME test_synchapi SOURCES test/test_synchapi.c)
+        wibo_add_fixture_bin(NAME test_processes SOURCES test/test_processes.c)
+        wibo_add_fixture_bin(NAME test_heap SOURCES test/test_heap.c)
+        wibo_add_fixture_bin(NAME test_actctx SOURCES test/test_actctx.c)
+        wibo_add_fixture_bin(NAME test_overlapped_io SOURCES test/test_overlapped_io.c)
+        wibo_add_fixture_bin(NAME test_time SOURCES test/test_time.c)
+        wibo_add_fixture_bin(NAME test_virtualalloc SOURCES test/test_virtualalloc.c)
+        wibo_add_fixture_bin(NAME test_virtualquery SOURCES test/test_virtualquery.c)
+        wibo_add_fixture_bin(NAME test_rtl SOURCES test/test_rtl.c)
+        wibo_add_fixture_bin(NAME test_ntquery SOURCES test/test_ntquery.c)
+        wibo_add_fixture_bin(NAME test_ntreadfile SOURCES test/test_ntreadfile.c)
+        wibo_add_fixture_bin(NAME test_pipe_io SOURCES test/test_pipe_io.c)
+        wibo_add_fixture_bin(NAME test_sysdir SOURCES test/test_sysdir.c)
+
+        # DLLs for fixture tests
+        wibo_add_fixture_dll(NAME external_exports SOURCES test/external_exports.c)
+        wibo_add_fixture_dll(NAME dll_attach_failure SOURCES test/dll_attach_failure.c)
+        wibo_add_fixture_dll(NAME thread_notifications SOURCES test/thread_notifications.c)
+
+        # Resources for test_resources
+        add_custom_command(
+            OUTPUT ${WIBO_TEST_BIN_DIR}/test_resources_res.o
+            COMMAND ${WIBO_MINGW_WINDRES}
+                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_resources.rc
+                    -O coff -o test_resources_res.o
+            WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
+            DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/test/test_resources.rc)
+
+        add_custom_target(wibo_test_fixtures DEPENDS ${WIBO_TEST_FIXTURES})
+
+        if(CMAKE_CONFIGURATION_TYPES)
+            set(_wibo_fixture_build_command
+                ${CMAKE_COMMAND} --build ${CMAKE_BINARY_DIR} --config $<CONFIG> --target wibo_test_fixtures)
         else()
-            set(WIBO_TEST_BIN_DIR ${CMAKE_CURRENT_BINARY_DIR}/test)
-            file(MAKE_DIRECTORY ${WIBO_TEST_BIN_DIR})
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/external_exports.dll
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2 -shared
-                        -o external_exports.dll
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/external_exports.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/test/external_exports.c)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/dll_attach_failure.dll
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2 -shared
-                        -o dll_attach_failure.dll
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/dll_attach_failure.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/test/dll_attach_failure.c)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/thread_notifications.dll
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2 -shared
-                        -o thread_notifications.dll
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/thread_notifications.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/test/thread_notifications.c)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_external_dll.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_external_dll.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_external_dll.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_external_dll.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_dll_attach_failure.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_dll_attach_failure.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_dll_attach_failure.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_dll_attach_failure.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_thread_notifications.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_thread_notifications.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_thread_notifications.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_thread_notifications.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_bcrypt.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_bcrypt.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_bcrypt.c
-                        -lbcrypt
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_bcrypt.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_resources_res.o
-                COMMAND ${WIBO_MINGW_WINDRES}
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_resources.rc
-                        -O coff -o test_resources_res.o
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/test/test_resources.rc)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_resources.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_resources.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_resources.c
-                        test_resources_res.o -lversion
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_resources.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h
-                    ${WIBO_TEST_BIN_DIR}/test_resources_res.o)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_threading.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_threading.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_threading.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_threading.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_handleapi.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_handleapi.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_handleapi.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_handleapi.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_findfile.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_findfile.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_findfile.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_findfile.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_synchapi.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_synchapi.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_synchapi.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_synchapi.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_processes.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_processes.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_processes.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_processes.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_heap.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_heap.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_heap.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_heap.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_actctx.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_actctx.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_actctx.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_actctx.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_overlapped_io.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_overlapped_io.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_overlapped_io.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_overlapped_io.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_time.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_time.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_time.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_time.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_virtualalloc.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_virtualalloc.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_virtualalloc.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_virtualalloc.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_virtualquery.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_virtualquery.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_virtualquery.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_virtualquery.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_rtl.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_rtl.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_rtl.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_rtl.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_ntquery.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_ntquery.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_ntquery.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_ntquery.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_ntreadfile.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_ntreadfile.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_ntreadfile.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_ntreadfile.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_pipe_io.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_pipe_io.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_pipe_io.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_pipe_io.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_command(
-                OUTPUT ${WIBO_TEST_BIN_DIR}/test_sysdir.exe
-                COMMAND ${WIBO_MINGW_CC} -Wall -Wextra -O2
-                        -I${CMAKE_CURRENT_SOURCE_DIR}/test
-                        -o test_sysdir.exe
-                        ${CMAKE_CURRENT_SOURCE_DIR}/test/test_sysdir.c
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_sysdir.c
-                    ${CMAKE_CURRENT_SOURCE_DIR}/test/test_assert.h)
-
-            add_custom_target(wibo_test_fixtures
-                DEPENDS
-                    ${WIBO_TEST_BIN_DIR}/external_exports.dll
-                    ${WIBO_TEST_BIN_DIR}/dll_attach_failure.dll
-                    ${WIBO_TEST_BIN_DIR}/thread_notifications.dll
-                    ${WIBO_TEST_BIN_DIR}/test_external_dll.exe
-                    ${WIBO_TEST_BIN_DIR}/test_dll_attach_failure.exe
-                    ${WIBO_TEST_BIN_DIR}/test_thread_notifications.exe
-                    ${WIBO_TEST_BIN_DIR}/test_bcrypt.exe
-                    ${WIBO_TEST_BIN_DIR}/test_resources.exe
-                    ${WIBO_TEST_BIN_DIR}/test_threading.exe
-                    ${WIBO_TEST_BIN_DIR}/test_handleapi.exe
-                    ${WIBO_TEST_BIN_DIR}/test_findfile.exe
-                    ${WIBO_TEST_BIN_DIR}/test_synchapi.exe
-                    ${WIBO_TEST_BIN_DIR}/test_processes.exe
-                    ${WIBO_TEST_BIN_DIR}/test_heap.exe
-                    ${WIBO_TEST_BIN_DIR}/test_actctx.exe
-                    ${WIBO_TEST_BIN_DIR}/test_overlapped_io.exe
-                    ${WIBO_TEST_BIN_DIR}/test_time.exe
-                    ${WIBO_TEST_BIN_DIR}/test_virtualalloc.exe
-                    ${WIBO_TEST_BIN_DIR}/test_virtualquery.exe
-                    ${WIBO_TEST_BIN_DIR}/test_rtl.exe
-                    ${WIBO_TEST_BIN_DIR}/test_ntquery.exe
-                    ${WIBO_TEST_BIN_DIR}/test_ntreadfile.exe
-                    ${WIBO_TEST_BIN_DIR}/test_pipe_io.exe
-                    ${WIBO_TEST_BIN_DIR}/test_sysdir.exe)
-
-            if(CMAKE_CONFIGURATION_TYPES)
-                set(_wibo_fixture_build_command
-                    ${CMAKE_COMMAND} --build ${CMAKE_BINARY_DIR} --config $<CONFIG> --target wibo_test_fixtures)
-            else()
-                set(_wibo_fixture_build_command
-                    ${CMAKE_COMMAND} --build ${CMAKE_BINARY_DIR} --target wibo_test_fixtures)
-            endif()
-
-            add_test(NAME wibo.build_fixtures COMMAND ${_wibo_fixture_build_command})
-
-            add_test(NAME wibo.test_external_dll
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_external_dll.exe)
-            set_tests_properties(wibo.test_external_dll PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_bcrypt
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_bcrypt.exe)
-            set_tests_properties(wibo.test_bcrypt PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_resources
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_resources.exe)
-            set_tests_properties(wibo.test_resources PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_threading
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_threading.exe)
-            set_tests_properties(wibo.test_threading PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_handleapi
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_handleapi.exe)
-            set_tests_properties(wibo.test_handleapi PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_findfile
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_findfile.exe)
-            set_tests_properties(wibo.test_findfile PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_synchapi
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_synchapi.exe)
-            set_tests_properties(wibo.test_synchapi PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_processes
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_processes.exe)
-            set_tests_properties(wibo.test_processes PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_heap
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_heap.exe)
-            set_tests_properties(wibo.test_heap PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_actctx
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_actctx.exe)
-            set_tests_properties(wibo.test_actctx PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_overlapped_io
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_overlapped_io.exe)
-            set_tests_properties(wibo.test_overlapped_io PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_time
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_time.exe)
-            set_tests_properties(wibo.test_time PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_virtualalloc
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_virtualalloc.exe)
-            set_tests_properties(wibo.test_virtualalloc PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_virtualquery
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_virtualquery.exe)
-            set_tests_properties(wibo.test_virtualquery PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_rtl
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_rtl.exe)
-            set_tests_properties(wibo.test_rtl PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_ntquery
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_ntquery.exe)
-            set_tests_properties(wibo.test_ntquery PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_ntreadfile
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_ntreadfile.exe)
-            set_tests_properties(wibo.test_ntreadfile PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_pipe_io
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_pipe_io.exe)
-            set_tests_properties(wibo.test_pipe_io PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_sysdir
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_sysdir.exe)
-            set_tests_properties(wibo.test_sysdir PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_dll_attach_failure
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_dll_attach_failure.exe)
-            set_tests_properties(wibo.test_dll_attach_failure PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
-
-            add_test(NAME wibo.test_thread_notifications
-                COMMAND $<TARGET_FILE:wibo> ${WIBO_TEST_BIN_DIR}/test_thread_notifications.exe)
-            set_tests_properties(wibo.test_thread_notifications PROPERTIES
-                WORKING_DIRECTORY ${WIBO_TEST_BIN_DIR}
-                DEPENDS wibo.build_fixtures)
+            set(_wibo_fixture_build_command
+                ${CMAKE_COMMAND} --build ${CMAKE_BINARY_DIR} --target wibo_test_fixtures)
         endif()
+
+        add_test(NAME wibo.build_fixtures COMMAND ${_wibo_fixture_build_command})
     endif()
 endif()
diff --git a/Dockerfile b/Dockerfile
index 476f67c..6d4ae2e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,6 +6,7 @@ RUN apk add --no-cache \
     bash \
     binutils \
     cmake \
+    coreutils \
     g++ \
     git \
     linux-headers \
@@ -19,18 +20,21 @@ WORKDIR /wibo
 COPY . /wibo
 
 # Build type (Release, Debug, RelWithDebInfo, MinSizeRel)
-ARG build_type=Release
+ARG BUILD_TYPE=Release
+
+# Enable link-time optimization (LTO) (AUTO, ON, OFF)
+ARG ENABLE_LTO=AUTO
 
 # Build static binary
 RUN cmake -S /wibo -B /wibo/build -G Ninja \
-        -DCMAKE_BUILD_TYPE="$build_type" \
-        -DCMAKE_C_FLAGS="-static" \
-        -DCMAKE_CXX_FLAGS="-static" \
-        -DBUILD_TESTING=ON \
-        -DWIBO_ENABLE_FIXTURE_TESTS=ON \
-        -DMI_LIBC_MUSL=ON \
-    && cmake --build /wibo/build \
-    && ( [ "$build_type" != "Release" ] || strip -g /wibo/build/wibo )
+        -DCMAKE_BUILD_TYPE:STRING="$BUILD_TYPE" \
+        -DCMAKE_C_FLAGS:STRING="-static" \
+        -DCMAKE_CXX_FLAGS:STRING="-static" \
+        -DMI_LIBC_MUSL:BOOL=ON \
+        -DWIBO_ENABLE_LIBURING:BOOL=ON \
+        -DWIBO_ENABLE_LTO:STRING="$ENABLE_LTO" \
+    && cmake --build /wibo/build --verbose \
+    && ( [ "$BUILD_TYPE" != "Release" ] || strip -g /wibo/build/wibo )
 
 # Export binary (usage: docker build --target export --output build .)
 FROM scratch AS export
diff --git a/Dockerfile.ubuntu b/Dockerfile.ubuntu
index 09d0a8c..a1f6cf9 100644
--- a/Dockerfile.ubuntu
+++ b/Dockerfile.ubuntu
@@ -25,14 +25,17 @@ WORKDIR /wibo
 COPY . /wibo
 
 # Build type (Release, Debug, RelWithDebInfo, MinSizeRel)
-ARG build_type=Release
+ARG BUILD_TYPE=Release
+
+# Enable link-time optimization (LTO) (AUTO, ON, OFF)
+ARG ENABLE_LTO=AUTO
 
 RUN cmake -S /wibo -B /wibo/build -G Ninja \
-        -DCMAKE_BUILD_TYPE="$build_type" \
-        -DBUILD_TESTING=ON \
-        -DWIBO_ENABLE_FIXTURE_TESTS=ON \
-    && cmake --build /wibo/build \
-    && ( [ "$build_type" != "Release" ] || strip -g /wibo/build/wibo )
+        -DCMAKE_BUILD_TYPE:STRING="$BUILD_TYPE" \
+        -DWIBO_ENABLE_LIBURING:BOOL=ON \
+        -DWIBO_ENABLE_LTO:STRING="$ENABLE_LTO" \
+    && cmake --build /wibo/build --verbose \
+    && ( [ "$BUILD_TYPE" != "Release" ] || strip -g /wibo/build/wibo )
 
 # Export binary (usage: docker build -f Dockerfile.ubuntu --target export --output dist .)
 FROM scratch AS export
diff --git a/README.md b/README.md
index 3592004..894d7ab 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ A minimal, low-fuss wrapper that can run simple command-line 32-bit Windows bina
 ## Building
 
 ```sh
-cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DBUILD_TESTING=ON
+cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
 cmake --build build
 ```
 
diff --git a/cmake/FindFilesystem.cmake b/cmake/FindFilesystem.cmake
deleted file mode 100644
index a152e52..0000000
--- a/cmake/FindFilesystem.cmake
+++ /dev/null
@@ -1,247 +0,0 @@
-# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
-# file Copyright.txt or https://cmake.org/licensing for details.
-
-#[=======================================================================[.rst:
-
-FindFilesystem
-##############
-
-This module supports the C++17 standard library's filesystem utilities. Use the
-:imp-target:`std::filesystem` imported target to
-
-Options
-*******
-
-The ``COMPONENTS`` argument to this module supports the following values:
-
-.. find-component:: Experimental
-    :name: fs.Experimental
-
-    Allows the module to find the "experimental" Filesystem TS version of the
-    Filesystem library. This is the library that should be used with the
-    ``std::experimental::filesystem`` namespace.
-
-.. find-component:: Final
-    :name: fs.Final
-
-    Finds the final C++17 standard version of the filesystem library.
-
-If no components are provided, behaves as if the
-:find-component:`fs.Final` component was specified.
-
-If both :find-component:`fs.Experimental` and :find-component:`fs.Final` are
-provided, first looks for ``Final``, and falls back to ``Experimental`` in case
-of failure. If ``Final`` is found, :imp-target:`std::filesystem` and all
-:ref:`variables <fs.variables>` will refer to the ``Final`` version.
-
-
-Imported Targets
-****************
-
-.. imp-target:: std::filesystem
-
-    The ``std::filesystem`` imported target is defined when any requested
-    version of the C++ filesystem library has been found, whether it is
-    *Experimental* or *Final*.
-
-    If no version of the filesystem library is available, this target will not
-    be defined.
-
-    .. note::
-        This target has ``cxx_std_17`` as an ``INTERFACE``
-        :ref:`compile language standard feature <req-lang-standards>`. Linking
-        to this target will automatically enable C++17 if no later standard
-        version is already required on the linking target.
-
-
-.. _fs.variables:
-
-Variables
-*********
-
-.. variable:: CXX_FILESYSTEM_IS_EXPERIMENTAL
-
-    Set to ``TRUE`` when the :find-component:`fs.Experimental` version of C++
-    filesystem library was found, otherwise ``FALSE``.
-
-.. variable:: CXX_FILESYSTEM_HAVE_FS
-
-    Set to ``TRUE`` when a filesystem header was found.
-
-.. variable:: CXX_FILESYSTEM_HEADER
-
-    Set to either ``filesystem`` or ``experimental/filesystem`` depending on
-    whether :find-component:`fs.Final` or :find-component:`fs.Experimental` was
-    found.
-
-.. variable:: CXX_FILESYSTEM_NAMESPACE
-
-    Set to either ``std::filesystem`` or ``std::experimental::filesystem``
-    depending on whether :find-component:`fs.Final` or
-    :find-component:`fs.Experimental` was found.
-
-
-Examples
-********
-
-Using `find_package(Filesystem)` with no component arguments:
-
-.. code-block:: cmake
-
-    find_package(Filesystem REQUIRED)
-
-    add_executable(my-program main.cpp)
-    target_link_libraries(my-program PRIVATE std::filesystem)
-
-
-#]=======================================================================]
-
-
-if(TARGET std::filesystem)
-    # This module has already been processed. Don't do it again.
-    return()
-endif()
-
-cmake_minimum_required(VERSION 3.10)
-
-include(CMakePushCheckState)
-include(CheckIncludeFileCXX)
-
-# If we're not cross-compiling, try to run test executables.
-# Otherwise, assume that compile + link is a sufficient check.
-if(CMAKE_CROSSCOMPILING)
-    include(CheckCXXSourceCompiles)
-    macro(_cmcm_check_cxx_source code var)
-        check_cxx_source_compiles("${code}" ${var})
-    endmacro()
-else()
-    include(CheckCXXSourceRuns)
-    macro(_cmcm_check_cxx_source code var)
-        check_cxx_source_runs("${code}" ${var})
-    endmacro()
-endif()
-
-cmake_push_check_state()
-
-set(CMAKE_REQUIRED_QUIET ${Filesystem_FIND_QUIETLY})
-
-# All of our tests required C++17 or later
-set(CMAKE_CXX_STANDARD 17)
-
-# Normalize and check the component list we were given
-set(want_components ${Filesystem_FIND_COMPONENTS})
-if(Filesystem_FIND_COMPONENTS STREQUAL "")
-    set(want_components Final)
-endif()
-
-# Warn on any unrecognized components
-set(extra_components ${want_components})
-list(REMOVE_ITEM extra_components Final Experimental)
-foreach(component IN LISTS extra_components)
-    message(WARNING "Extraneous find_package component for Filesystem: ${component}")
-endforeach()
-
-# Detect which of Experimental and Final we should look for
-set(find_experimental TRUE)
-set(find_final TRUE)
-if(NOT "Final" IN_LIST want_components)
-    set(find_final FALSE)
-endif()
-if(NOT "Experimental" IN_LIST want_components)
-    set(find_experimental FALSE)
-endif()
-
-if(find_final)
-    check_include_file_cxx("filesystem" _CXX_FILESYSTEM_HAVE_HEADER)
-    mark_as_advanced(_CXX_FILESYSTEM_HAVE_HEADER)
-    if(_CXX_FILESYSTEM_HAVE_HEADER)
-        # We found the non-experimental header. Don't bother looking for the
-        # experimental one.
-        set(find_experimental FALSE)
-    endif()
-else()
-    set(_CXX_FILESYSTEM_HAVE_HEADER FALSE)
-endif()
-
-if(find_experimental)
-    check_include_file_cxx("experimental/filesystem" _CXX_FILESYSTEM_HAVE_EXPERIMENTAL_HEADER)
-    mark_as_advanced(_CXX_FILESYSTEM_HAVE_EXPERIMENTAL_HEADER)
-else()
-    set(_CXX_FILESYSTEM_HAVE_EXPERIMENTAL_HEADER FALSE)
-endif()
-
-if(_CXX_FILESYSTEM_HAVE_HEADER)
-    set(_have_fs TRUE)
-    set(_fs_header filesystem)
-    set(_fs_namespace std::filesystem)
-    set(_is_experimental FALSE)
-elseif(_CXX_FILESYSTEM_HAVE_EXPERIMENTAL_HEADER)
-    set(_have_fs TRUE)
-    set(_fs_header experimental/filesystem)
-    set(_fs_namespace std::experimental::filesystem)
-    set(_is_experimental TRUE)
-else()
-    set(_have_fs FALSE)
-endif()
-
-set(CXX_FILESYSTEM_HAVE_FS ${_have_fs} CACHE BOOL "TRUE if we have the C++ filesystem headers")
-set(CXX_FILESYSTEM_HEADER ${_fs_header} CACHE STRING "The header that should be included to obtain the filesystem APIs")
-set(CXX_FILESYSTEM_NAMESPACE ${_fs_namespace} CACHE STRING "The C++ namespace that contains the filesystem APIs")
-set(CXX_FILESYSTEM_IS_EXPERIMENTAL ${_is_experimental} CACHE BOOL "TRUE if the C++ filesystem library is the experimental version")
-
-set(_found FALSE)
-
-if(CXX_FILESYSTEM_HAVE_FS)
-    # We have some filesystem library available. Do link checks
-    string(CONFIGURE [[
-        #include <cstdlib>
-        #include <@CXX_FILESYSTEM_HEADER@>
-
-        int main() {
-            auto cwd = @CXX_FILESYSTEM_NAMESPACE@::current_path();
-            printf("%s", cwd.c_str());
-            return EXIT_SUCCESS;
-        }
-    ]] code @ONLY)
-
-    # Check a simple filesystem program without any linker flags
-    _cmcm_check_cxx_source("${code}" CXX_FILESYSTEM_NO_LINK_NEEDED)
-
-    set(can_link ${CXX_FILESYSTEM_NO_LINK_NEEDED})
-
-    if(NOT CXX_FILESYSTEM_NO_LINK_NEEDED)
-        set(prev_libraries ${CMAKE_REQUIRED_LIBRARIES})
-        # Add the libstdc++ flag
-        set(CMAKE_REQUIRED_LIBRARIES ${prev_libraries} -lstdc++fs)
-        _cmcm_check_cxx_source("${code}" CXX_FILESYSTEM_STDCPPFS_NEEDED)
-        set(can_link ${CXX_FILESYSTEM_STDCPPFS_NEEDED})
-        if(NOT CXX_FILESYSTEM_STDCPPFS_NEEDED)
-            # Try the libc++ flag
-            set(CMAKE_REQUIRED_LIBRARIES ${prev_libraries} -lc++fs)
-            _cmcm_check_cxx_source("${code}" CXX_FILESYSTEM_CPPFS_NEEDED)
-            set(can_link ${CXX_FILESYSTEM_CPPFS_NEEDED})
-        endif()
-    endif()
-
-    if(can_link)
-        add_library(std::filesystem INTERFACE IMPORTED)
-        set_property(TARGET std::filesystem APPEND PROPERTY INTERFACE_COMPILE_FEATURES cxx_std_17)
-        set(_found TRUE)
-
-        if(CXX_FILESYSTEM_NO_LINK_NEEDED)
-            # Nothing to add...
-        elseif(CXX_FILESYSTEM_STDCPPFS_NEEDED)
-            set_property(TARGET std::filesystem APPEND PROPERTY INTERFACE_LINK_LIBRARIES -lstdc++fs)
-        elseif(CXX_FILESYSTEM_CPPFS_NEEDED)
-            set_property(TARGET std::filesystem APPEND PROPERTY INTERFACE_LINK_LIBRARIES -lc++fs)
-        endif()
-    endif()
-endif()
-
-cmake_pop_check_state()
-
-set(Filesystem_FOUND ${_found} CACHE BOOL "TRUE if we can run a program using std::filesystem" FORCE)
-
-if(Filesystem_FIND_REQUIRED AND NOT Filesystem_FOUND)
-    message(FATAL_ERROR "Cannot run simple program using std::filesystem")
-endif()
diff --git a/dll/advapi32.cpp b/dll/advapi32.cpp
index b35db8a..b2b559b 100644
--- a/dll/advapi32.cpp
+++ b/dll/advapi32.cpp
@@ -106,7 +106,7 @@ void *resolveByName(const char *name) {
 
 } // namespace
 
-wibo::ModuleStub lib_advapi32 = {
+extern const wibo::ModuleStub lib_advapi32 = {
 	(const char *[]){
 		"advapi32",
 		nullptr,
diff --git a/dll/bcrypt.cpp b/dll/bcrypt.cpp
index a743f76..da6d28c 100644
--- a/dll/bcrypt.cpp
+++ b/dll/bcrypt.cpp
@@ -74,7 +74,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_bcrypt = {
+extern const wibo::ModuleStub lib_bcrypt = {
 	(const char *[]){
 		"bcrypt",
 		nullptr,
diff --git a/dll/crt.cpp b/dll/crt.cpp
index c49eae7..f713677 100644
--- a/dll/crt.cpp
+++ b/dll/crt.cpp
@@ -463,7 +463,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_crt = {
+extern const wibo::ModuleStub lib_crt = {
 	(const char *[]){
 		"api-ms-win-crt-heap-l1-1-0",
 		"api-ms-win-crt-locale-l1-1-0",
diff --git a/dll/kernel32.cpp b/dll/kernel32.cpp
index 114bfbe..14dc483 100644
--- a/dll/kernel32.cpp
+++ b/dll/kernel32.cpp
@@ -9,8 +9,8 @@
 #include "kernel32/interlockedapi.h"
 #include "kernel32/ioapiset.h"
 #include "kernel32/libloaderapi.h"
-#include "kernel32/namedpipeapi.h"
 #include "kernel32/memoryapi.h"
+#include "kernel32/namedpipeapi.h"
 #include "kernel32/processenv.h"
 #include "kernel32/processthreadsapi.h"
 #include "kernel32/profileapi.h"
@@ -602,7 +602,7 @@ void *resolveByName(const char *name) {
 
 } // namespace
 
-wibo::ModuleStub lib_kernel32 = {
+extern const wibo::ModuleStub lib_kernel32 = {
 	(const char *[]){
 		"kernel32",
 		nullptr,
diff --git a/dll/kernel32/fibersapi.cpp b/dll/kernel32/fibersapi.cpp
index c763d09..019bb77 100644
--- a/dll/kernel32/fibersapi.cpp
+++ b/dll/kernel32/fibersapi.cpp
@@ -34,7 +34,7 @@ DWORD WIN_FUNC FlsAlloc(PFLS_CALLBACK_FUNCTION lpCallback) {
 BOOL WIN_FUNC FlsFree(DWORD dwFlsIndex) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("FlsFree(%u)\n", dwFlsIndex);
-	if (dwFlsIndex >= 0 && dwFlsIndex < kMaxFlsValues && g_flsValuesUsed[dwFlsIndex]) {
+	if (dwFlsIndex < kMaxFlsValues && g_flsValuesUsed[dwFlsIndex]) {
 		g_flsValuesUsed[dwFlsIndex] = false;
 		return TRUE;
 	} else {
@@ -47,7 +47,7 @@ PVOID WIN_FUNC FlsGetValue(DWORD dwFlsIndex) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("FlsGetValue(%u)\n", dwFlsIndex);
 	PVOID result = nullptr;
-	if (dwFlsIndex >= 0 && dwFlsIndex < kMaxFlsValues && g_flsValuesUsed[dwFlsIndex]) {
+	if (dwFlsIndex < kMaxFlsValues && g_flsValuesUsed[dwFlsIndex]) {
 		result = g_flsValues[dwFlsIndex];
 		// See https://learn.microsoft.com/en-us/windows/win32/api/fibersapi/nf-fibersapi-flsgetvalue
 		wibo::lastError = ERROR_SUCCESS;
@@ -61,7 +61,7 @@ PVOID WIN_FUNC FlsGetValue(DWORD dwFlsIndex) {
 BOOL WIN_FUNC FlsSetValue(DWORD dwFlsIndex, PVOID lpFlsData) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("FlsSetValue(%u, %p)\n", dwFlsIndex, lpFlsData);
-	if (dwFlsIndex >= 0 && dwFlsIndex < kMaxFlsValues && g_flsValuesUsed[dwFlsIndex]) {
+	if (dwFlsIndex < kMaxFlsValues && g_flsValuesUsed[dwFlsIndex]) {
 		g_flsValues[dwFlsIndex] = lpFlsData;
 		return TRUE;
 	} else {
diff --git a/dll/kernel32/fileapi.cpp b/dll/kernel32/fileapi.cpp
index 92ec82f..9c23ac9 100644
--- a/dll/kernel32/fileapi.cpp
+++ b/dll/kernel32/fileapi.cpp
@@ -717,11 +717,11 @@ BOOL WIN_FUNC WriteFile(HANDLE hFile, LPCVOID lpBuffer, DWORD nNumberOfBytesToWr
 		return FALSE;
 	}
 
-	std::optional<off64_t> offset;
+	std::optional<off_t> offset;
 	bool updateFilePointer = true;
 	if (lpOverlapped != nullptr) {
-		offset = static_cast<off64_t>((static_cast<uint64_t>(lpOverlapped->Offset)) |
-									  (static_cast<uint64_t>(lpOverlapped->OffsetHigh) << 32));
+		offset = static_cast<off_t>((static_cast<uint64_t>(lpOverlapped->Offset)) |
+									(static_cast<uint64_t>(lpOverlapped->OffsetHigh) << 32));
 		lpOverlapped->Internal = STATUS_PENDING;
 		lpOverlapped->InternalHigh = 0;
 		updateFilePointer = !file->overlapped;
@@ -736,9 +736,8 @@ BOOL WIN_FUNC WriteFile(HANDLE hFile, LPCVOID lpBuffer, DWORD nNumberOfBytesToWr
 				}
 				return TRUE;
 			}
-			auto asyncFile = file.clone();
-			if (async_io::queueWrite(std::move(asyncFile), lpOverlapped, lpBuffer, nNumberOfBytesToWrite, offset,
-									 file->isPipe)) {
+			if (wibo::asyncIO().queueWrite(file.clone(), lpOverlapped, lpBuffer, nNumberOfBytesToWrite, offset,
+										   file->isPipe)) {
 				if (lpNumberOfBytesWritten) {
 					*lpNumberOfBytesWritten = 0;
 				}
@@ -814,11 +813,11 @@ BOOL WIN_FUNC ReadFile(HANDLE hFile, LPVOID lpBuffer, DWORD nNumberOfBytesToRead
 		*lpNumberOfBytesRead = 0;
 	}
 
-	std::optional<off64_t> offset;
+	std::optional<off_t> offset;
 	bool updateFilePointer = true;
 	if (lpOverlapped != nullptr) {
-		offset = static_cast<off64_t>((static_cast<uint64_t>(lpOverlapped->Offset)) |
-									  (static_cast<uint64_t>(lpOverlapped->OffsetHigh) << 32));
+		offset = static_cast<off_t>((static_cast<uint64_t>(lpOverlapped->Offset)) |
+									(static_cast<uint64_t>(lpOverlapped->OffsetHigh) << 32));
 		lpOverlapped->Internal = STATUS_PENDING;
 		lpOverlapped->InternalHigh = 0;
 		updateFilePointer = !file->overlapped;
@@ -833,7 +832,8 @@ BOOL WIN_FUNC ReadFile(HANDLE hFile, LPVOID lpBuffer, DWORD nNumberOfBytesToRead
 				}
 				return TRUE;
 			}
-			if (async_io::queueRead(file.clone(), lpOverlapped, lpBuffer, nNumberOfBytesToRead, offset, file->isPipe)) {
+			if (wibo::asyncIO().queueRead(file.clone(), lpOverlapped, lpBuffer, nNumberOfBytesToRead, offset,
+										  file->isPipe)) {
 				if (lpNumberOfBytesRead) {
 					*lpNumberOfBytesRead = 0;
 				}
@@ -1193,14 +1193,14 @@ DWORD WIN_FUNC SetFilePointer(HANDLE hFile, LONG lDistanceToMove, PLONG lpDistan
 	}
 	// TODO access check
 	std::lock_guard lk(file->m);
-	off64_t position = 0;
-	off64_t offset = static_cast<off64_t>(lDistanceToMove);
+	off_t position = 0;
+	off_t offset = static_cast<off_t>(lDistanceToMove);
 	if (dwMoveMethod == FILE_BEGIN) {
 		position = offset;
 	} else if (dwMoveMethod == FILE_CURRENT) {
 		position = file->filePos + offset;
 	} else if (dwMoveMethod == FILE_END) {
-		position = lseek64(file->fd, offset, SEEK_END);
+		position = lseek(file->fd, offset, SEEK_END);
 	}
 	if (position < 0) {
 		if (errno == EINVAL) {
@@ -1232,14 +1232,14 @@ BOOL WIN_FUNC SetFilePointerEx(HANDLE hFile, LARGE_INTEGER liDistanceToMove, PLA
 	}
 	// TODO access check
 	std::lock_guard lk(file->m);
-	off64_t position = 0;
-	off64_t offset = static_cast<off64_t>(liDistanceToMove);
+	off_t position = 0;
+	off_t offset = static_cast<off_t>(liDistanceToMove);
 	if (dwMoveMethod == FILE_BEGIN) {
 		position = offset;
 	} else if (dwMoveMethod == FILE_CURRENT) {
 		position = file->filePos + offset;
 	} else if (dwMoveMethod == FILE_END) {
-		position = lseek64(file->fd, offset, SEEK_END);
+		position = lseek(file->fd, offset, SEEK_END);
 	}
 	if (position < 0) {
 		if (errno == EINVAL) {
@@ -1279,7 +1279,7 @@ BOOL WIN_FUNC SetEndOfFile(HANDLE hFile) {
 		setLastErrorFromErrno();
 		return FALSE;
 	}
-	if (ftruncate64(file->fd, file->filePos) != 0) {
+	if (ftruncate(file->fd, file->filePos) != 0) {
 		setLastErrorFromErrno();
 		return FALSE;
 	}
@@ -1338,7 +1338,7 @@ DWORD WIN_FUNC GetFileSize(HANDLE hFile, LPDWORD lpFileSizeHigh) {
 		DEBUG_LOG("-> INVALID_FILE_SIZE (ERROR_INVALID_HANDLE)\n");
 		return INVALID_FILE_SIZE;
 	}
-	const auto size = lseek64(file->fd, 0, SEEK_END);
+	const auto size = lseek(file->fd, 0, SEEK_END);
 	if (size < 0) {
 		if (lpFileSizeHigh) {
 			*lpFileSizeHigh = 0;
@@ -1480,8 +1480,8 @@ BOOL WIN_FUNC GetFileInformationByHandle(HANDLE hFile, LPBY_HANDLE_FILE_INFORMAT
 		return FALSE;
 	}
 	// TODO access check
-	struct stat64 st{};
-	if (fstat64(file->fd, &st) != 0) {
+	struct stat st{};
+	if (fstat(file->fd, &st) != 0) {
 		setLastErrorFromErrno();
 		return FALSE;
 	}
diff --git a/dll/kernel32/interlockedapi.cpp b/dll/kernel32/interlockedapi.cpp
index 9e06ded..ea3b70f 100644
--- a/dll/kernel32/interlockedapi.cpp
+++ b/dll/kernel32/interlockedapi.cpp
@@ -3,6 +3,7 @@
 #include "common.h"
 #include "context.h"
 
+#include <atomic>
 #include <cstring>
 
 namespace kernel32 {
@@ -10,32 +11,33 @@ namespace kernel32 {
 LONG WIN_FUNC InterlockedIncrement(LONG volatile *Addend) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("InterlockedIncrement(%p)\n", Addend);
-	return ++(*Addend);
+	std::atomic_ref<LONG> a(*const_cast<LONG *>(Addend));
+	return a.fetch_add(1, std::memory_order_seq_cst) + 1;
 }
 
 LONG WIN_FUNC InterlockedDecrement(LONG volatile *Addend) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("InterlockedDecrement(%p)\n", Addend);
-	return --(*Addend);
+	std::atomic_ref<LONG> a(*const_cast<LONG *>(Addend));
+	return a.fetch_sub(1, std::memory_order_seq_cst) - 1;
 }
 
 LONG WIN_FUNC InterlockedExchange(LONG volatile *Target, LONG Value) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("InterlockedExchange(%p, %ld)\n", Target, static_cast<long>(Value));
-	LONG initial = *Target;
-	*Target = Value;
-	return initial;
+	std::atomic_ref<LONG> a(*const_cast<LONG *>(Target));
+	return a.exchange(Value, std::memory_order_seq_cst);
 }
 
 LONG WIN_FUNC InterlockedCompareExchange(LONG volatile *Destination, LONG Exchange, LONG Comperand) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("InterlockedCompareExchange(%p, %ld, %ld)\n", Destination, static_cast<long>(Exchange),
 				static_cast<long>(Comperand));
-	LONG original = *Destination;
-	if (original == Comperand) {
-		*Destination = Exchange;
-	}
-	return original;
+
+	std::atomic_ref<LONG> a(*const_cast<LONG *>(Destination));
+	LONG expected = Comperand;
+	a.compare_exchange_strong(expected, Exchange, std::memory_order_seq_cst);
+	return expected;
 }
 
 void WIN_FUNC InitializeSListHead(PSLIST_HEADER ListHead) {
diff --git a/dll/kernel32/internal.h b/dll/kernel32/internal.h
index 919ba39..79b2330 100644
--- a/dll/kernel32/internal.h
+++ b/dll/kernel32/internal.h
@@ -26,14 +26,14 @@ struct FsObject : ObjectBase {
 struct FileObject final : FsObject {
 	static constexpr ObjectType kType = ObjectType::File;
 
-	off64_t filePos = 0;
+	off_t filePos = 0;
 	bool overlapped = false;
 	bool appendOnly = false;
 	bool isPipe = false;
 
 	explicit FileObject(int fd) : FsObject(kType, fd) {
 		if (fd >= 0) {
-			off64_t pos = lseek64(fd, 0, SEEK_CUR);
+			off_t pos = lseek(fd, 0, SEEK_CUR);
 			if (pos == -1 && errno == ESPIPE) {
 				isPipe = true;
 			} else if (pos >= 0) {
diff --git a/dll/kernel32/libloaderapi.cpp b/dll/kernel32/libloaderapi.cpp
index 807a833..f5fe941 100644
--- a/dll/kernel32/libloaderapi.cpp
+++ b/dll/kernel32/libloaderapi.cpp
@@ -250,7 +250,8 @@ HMODULE WIN_FUNC LoadLibraryW(LPCWSTR lpLibFileName) {
 
 HMODULE WIN_FUNC LoadLibraryExW(LPCWSTR lpLibFileName, HANDLE hFile, DWORD dwFlags) {
 	HOST_CONTEXT_GUARD();
-	assert(!hFile);
+	(void)hFile;
+	// TOOD: handle dwFlags properly
 	DEBUG_LOG("LoadLibraryExW(%x) -> ", dwFlags);
 	auto filename = wideStringToString(lpLibFileName);
 	return LoadLibraryA(filename.c_str());
diff --git a/dll/kernel32/memoryapi.cpp b/dll/kernel32/memoryapi.cpp
index 7f97182..b51358a 100644
--- a/dll/kernel32/memoryapi.cpp
+++ b/dll/kernel32/memoryapi.cpp
@@ -502,7 +502,7 @@ HANDLE WIN_FUNC CreateFileMappingA(HANDLE hFile, LPSECURITY_ATTRIBUTES lpFileMap
 		}
 		mapping->fd = dupFd;
 		if (size == 0) {
-			off64_t fileSize = lseek64(dupFd, 0, SEEK_END);
+			off_t fileSize = lseek(dupFd, 0, SEEK_END);
 			if (fileSize < 0) {
 				return nullptr;
 			}
diff --git a/dll/kernel32/synchapi.cpp b/dll/kernel32/synchapi.cpp
index 9dd0bd4..2214410 100644
--- a/dll/kernel32/synchapi.cpp
+++ b/dll/kernel32/synchapi.cpp
@@ -635,26 +635,31 @@ BOOL WIN_FUNC InitOnceComplete(LPINIT_ONCE lpInitOnce, DWORD dwFlags, LPVOID lpC
 
 void WIN_FUNC AcquireSRWLockShared(PSRWLOCK SRWLock) {
 	HOST_CONTEXT_GUARD();
+	(void)SRWLock;
 	VERBOSE_LOG("STUB: AcquireSRWLockShared(%p)\n", SRWLock);
 }
 
 void WIN_FUNC ReleaseSRWLockShared(PSRWLOCK SRWLock) {
 	HOST_CONTEXT_GUARD();
+	(void)SRWLock;
 	VERBOSE_LOG("STUB: ReleaseSRWLockShared(%p)\n", SRWLock);
 }
 
 void WIN_FUNC AcquireSRWLockExclusive(PSRWLOCK SRWLock) {
 	HOST_CONTEXT_GUARD();
+	(void)SRWLock;
 	VERBOSE_LOG("STUB: AcquireSRWLockExclusive(%p)\n", SRWLock);
 }
 
 void WIN_FUNC ReleaseSRWLockExclusive(PSRWLOCK SRWLock) {
 	HOST_CONTEXT_GUARD();
+	(void)SRWLock;
 	VERBOSE_LOG("STUB: ReleaseSRWLockExclusive(%p)\n", SRWLock);
 }
 
 BOOLEAN WIN_FUNC TryAcquireSRWLockExclusive(PSRWLOCK SRWLock) {
 	HOST_CONTEXT_GUARD();
+	(void)SRWLock;
 	VERBOSE_LOG("STUB: TryAcquireSRWLockExclusive(%p)\n", SRWLock);
 	return TRUE;
 }
diff --git a/dll/kernel32/timeutil.h b/dll/kernel32/timeutil.h
index 3492c3b..b30af51 100644
--- a/dll/kernel32/timeutil.h
+++ b/dll/kernel32/timeutil.h
@@ -72,16 +72,16 @@ inline bool validateSystemTime(const SYSTEMTIME &st) {
 	if (st.wDay < 1 || st.wDay > static_cast<short>(daysInMonth(st.wYear, static_cast<unsigned>(st.wMonth)))) {
 		return false;
 	}
-	if (st.wHour < 0 || st.wHour > 23) {
+	if (st.wHour > 23) {
 		return false;
 	}
-	if (st.wMinute < 0 || st.wMinute > 59) {
+	if (st.wMinute > 59) {
 		return false;
 	}
-	if (st.wSecond < 0 || st.wSecond > 59) {
+	if (st.wSecond > 59) {
 		return false;
 	}
-	if (st.wMilliseconds < 0 || st.wMilliseconds > 999) {
+	if (st.wMilliseconds > 999) {
 		return false;
 	}
 	return true;
diff --git a/dll/lmgr.cpp b/dll/lmgr.cpp
index 9842a7a..4ab6c62 100644
--- a/dll/lmgr.cpp
+++ b/dll/lmgr.cpp
@@ -27,7 +27,7 @@ static void *resolveByOrdinal(uint16_t ordinal) {
 	return 0;
 }
 
-wibo::ModuleStub lib_lmgr = {
+extern const wibo::ModuleStub lib_lmgr = {
 	(const char *[]){
 		"lmgr11",
 		"lmgr326b",
diff --git a/dll/mscoree.cpp b/dll/mscoree.cpp
index 46016f6..bd270a4 100644
--- a/dll/mscoree.cpp
+++ b/dll/mscoree.cpp
@@ -18,7 +18,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_mscoree = {
+extern const wibo::ModuleStub lib_mscoree = {
 	(const char *[]){
 		"mscoree",
 		nullptr,
diff --git a/dll/msvcrt.cpp b/dll/msvcrt.cpp
index 0080676..c324bb6 100644
--- a/dll/msvcrt.cpp
+++ b/dll/msvcrt.cpp
@@ -2600,6 +2600,7 @@ namespace msvcrt {
 		HOST_CONTEXT_GUARD();
 		VERBOSE_LOG("_itow_s(%d, %p, %zu, %d)\n", value, buffer, size, radix);
 		if (!buffer || size == 0) return 22;
+		(void)radix;
 		assert(radix == 10); // only base 10 supported for now
 
 		std::string str = std::to_string(value);
@@ -3222,7 +3223,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_msvcrt = {
+extern const wibo::ModuleStub lib_msvcrt = {
 	(const char *[]){
 		"msvcrt",
 		"msvcrt40",
diff --git a/dll/ntdll.cpp b/dll/ntdll.cpp
index a0b6447..a485ad1 100644
--- a/dll/ntdll.cpp
+++ b/dll/ntdll.cpp
@@ -152,9 +152,9 @@ NTSTATUS WIN_FUNC NtReadFile(HANDLE FileHandle, HANDLE Event, PIO_APC_ROUTINE Ap
 		useCurrentFilePosition = true;
 	}
 
-	std::optional<off64_t> offset;
+	std::optional<off_t> offset;
 	if (!useCurrentFilePosition) {
-		offset = static_cast<off64_t>(*ByteOffset);
+		offset = static_cast<off_t>(*ByteOffset);
 	}
 
 	if (useOverlapped && useCurrentFilePosition) {
@@ -423,7 +423,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_ntdll = {
+extern const wibo::ModuleStub lib_ntdll = {
 	(const char *[]){
 		"ntdll",
 		nullptr,
diff --git a/dll/ole32.cpp b/dll/ole32.cpp
index 7866618..43c72b2 100644
--- a/dll/ole32.cpp
+++ b/dll/ole32.cpp
@@ -39,7 +39,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_ole32 = {
+extern const wibo::ModuleStub lib_ole32 = {
 	(const char *[]){
 		"ole32",
 		nullptr,
diff --git a/dll/rpcrt4.cpp b/dll/rpcrt4.cpp
index beb20e1..c6d13d7 100644
--- a/dll/rpcrt4.cpp
+++ b/dll/rpcrt4.cpp
@@ -285,7 +285,7 @@ void *resolveByName(const char *name) {
 
 } // namespace
 
-wibo::ModuleStub lib_rpcrt4 = {
+extern const wibo::ModuleStub lib_rpcrt4 = {
 	(const char *[]){"rpcrt4", nullptr},
 	resolveByName,
 	nullptr,
diff --git a/dll/user32.cpp b/dll/user32.cpp
index 7e5db14..9abe99e 100644
--- a/dll/user32.cpp
+++ b/dll/user32.cpp
@@ -120,6 +120,8 @@ namespace user32 {
 
 	int WIN_FUNC MessageBoxA(void *hwnd, const char *lpText, const char *lpCaption, unsigned int uType) {
 		HOST_CONTEXT_GUARD();
+		(void)hwnd;
+		(void)uType;
 		printf("MESSAGE BOX: [%s] %s\n", lpCaption, lpText);
 		fflush(stdout);
 		return 1;
@@ -183,7 +185,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_user32 = {
+extern const wibo::ModuleStub lib_user32 = {
 	(const char *[]){
 		"user32",
 		nullptr,
diff --git a/dll/vcruntime.cpp b/dll/vcruntime.cpp
index 9e45c0a..2e93c83 100644
--- a/dll/vcruntime.cpp
+++ b/dll/vcruntime.cpp
@@ -38,7 +38,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_vcruntime = {
+extern const wibo::ModuleStub lib_vcruntime = {
 	(const char *[]){
 		"vcruntime140",
 		nullptr,
diff --git a/dll/version.cpp b/dll/version.cpp
index c95107f..d90c78d 100644
--- a/dll/version.cpp
+++ b/dll/version.cpp
@@ -327,7 +327,7 @@ static void *resolveByName(const char *name) {
 	return nullptr;
 }
 
-wibo::ModuleStub lib_version = {
+extern const wibo::ModuleStub lib_version = {
 	(const char *[]){
 		"version",
 		nullptr,
diff --git a/src/async_io.cpp b/src/async_io.cpp
index bad2a6c..aa9b105 100644
--- a/src/async_io.cpp
+++ b/src/async_io.cpp
@@ -1,277 +1,56 @@
 #include "async_io.h"
 
-#include "common.h"
-#include "errors.h"
-#include "kernel32/overlapped_util.h"
+#include <memory>
 
-#include <atomic>
-#include <cassert>
-#include <cerrno>
-#include <condition_variable>
-#include <liburing.h>
-#include <mutex>
-#include <optional>
-#include <thread>
-#include <unistd.h>
-
-namespace async_io {
 namespace {
 
-constexpr unsigned kQueueDepth = 64;
+std::unique_ptr<wibo::AsyncIOBackend> g_backend;
 
-struct AsyncRequest {
-	enum class Kind { Read, Write, Shutdown };
-
-	Kind kind;
-	Pin<kernel32::FileObject> file;
-	OVERLAPPED *overlapped = nullptr;
-	bool isPipe = false;
-	struct iovec vec{};
-};
-
-class IoUringBackend {
+class DummyBackend : public wibo::AsyncIOBackend {
   public:
-	~IoUringBackend() { shutdown(); }
-	bool init();
-	void shutdown();
-	[[nodiscard]] bool running() const noexcept { return mRunning.load(std::memory_order_acquire); }
+	bool init() override { return true; }
+	void shutdown() override {}
+	[[nodiscard]] bool running() const noexcept override { return true; }
 
 	bool queueRead(Pin<kernel32::FileObject> file, OVERLAPPED *ov, void *buffer, DWORD length,
-				   const std::optional<off64_t> &offset, bool isPipe);
+				   const std::optional<off_t> &offset, bool isPipe) override {
+		(void)file;
+		(void)ov;
+		(void)buffer;
+		(void)length;
+		(void)offset;
+		(void)isPipe;
+		return false;
+	}
 	bool queueWrite(Pin<kernel32::FileObject> file, OVERLAPPED *ov, const void *buffer, DWORD length,
-					const std::optional<off64_t> &offset, bool isPipe);
-
-  private:
-	bool enqueueRequest(AsyncRequest *req, void *buffer, DWORD length, const std::optional<off64_t> &offset,
-						bool isWrite);
-	void requestStop();
-	void workerLoop();
-	void handleCompletion(struct io_uring_cqe *cqe);
-	void notifySpace();
-
-	struct io_uring mRing{};
-	std::mutex mSubmitMutex;
-	std::condition_variable mQueueCv;
-	std::atomic<bool> mRunning{false};
-	std::atomic<uint32_t> mPending{0};
-	std::thread mThread;
+					const std::optional<off_t> &offset, bool isPipe) override {
+		(void)file;
+		(void)ov;
+		(void)buffer;
+		(void)length;
+		(void)offset;
+		(void)isPipe;
+		return false;
+	}
 };
 
-IoUringBackend gBackend;
-
 } // namespace
 
-bool initialize() {
-	if (gBackend.running()) {
-		return true;
+namespace wibo {
+
+AsyncIOBackend &asyncIO() {
+	if (!g_backend) {
+#if WIBO_ENABLE_LIBURING
+		g_backend = detail::createIoUringBackend();
+#else
+		g_backend = std::make_unique<DummyBackend>();
+#endif
 	}
-	return gBackend.init();
+	if (!g_backend->init()) {
+		fprintf(stderr, "asyncIO: failed to initialize backend\n");
+		abort();
+	}
+	return *g_backend;
 }
 
-void shutdown() { gBackend.shutdown(); }
-
-bool running() { return gBackend.running(); }
-
-bool queueRead(Pin<kernel32::FileObject> file, OVERLAPPED *ov, void *buffer, DWORD length,
-			   const std::optional<off64_t> &offset, bool isPipe) {
-	if (!gBackend.running()) {
-		return false;
-	}
-	return gBackend.queueRead(std::move(file), ov, buffer, length, offset, isPipe);
-}
-
-bool queueWrite(Pin<kernel32::FileObject> file, OVERLAPPED *ov, const void *buffer, DWORD length,
-				const std::optional<off64_t> &offset, bool isPipe) {
-	if (!gBackend.running()) {
-		return false;
-	}
-	return gBackend.queueWrite(std::move(file), ov, buffer, length, offset, isPipe);
-}
-
-bool IoUringBackend::init() {
-	if (mRunning.load(std::memory_order_acquire)) {
-		return true;
-	}
-	int rc = io_uring_queue_init(kQueueDepth, &mRing, 0);
-	if (rc < 0) {
-		DEBUG_LOG("io_uring_queue_init failed: %d\n", rc);
-		return false;
-	}
-	mRunning.store(true, std::memory_order_release);
-	mThread = std::thread(&IoUringBackend::workerLoop, this);
-	DEBUG_LOG("io_uring backend initialized (depth=%u)\n", kQueueDepth);
-	return true;
-}
-
-void IoUringBackend::shutdown() {
-	if (!mRunning.exchange(false, std::memory_order_acq_rel)) {
-		return;
-	}
-	requestStop();
-	if (mThread.joinable()) {
-		mThread.join();
-	}
-	io_uring_queue_exit(&mRing);
-}
-
-bool IoUringBackend::queueRead(Pin<kernel32::FileObject> file, OVERLAPPED *ov, void *buffer, DWORD length,
-							   const std::optional<off64_t> &offset, bool isPipe) {
-	auto *req = new AsyncRequest{AsyncRequest::Kind::Read, std::move(file), ov, isPipe};
-	if (!enqueueRequest(req, buffer, length, offset, false)) {
-		delete req;
-		return false;
-	}
-	return true;
-}
-
-bool IoUringBackend::queueWrite(Pin<kernel32::FileObject> file, OVERLAPPED *ov, const void *buffer, DWORD length,
-								const std::optional<off64_t> &offset, bool isPipe) {
-	auto *req = new AsyncRequest{AsyncRequest::Kind::Write, std::move(file), ov, isPipe};
-	if (!enqueueRequest(req, const_cast<void *>(buffer), length, offset, true)) {
-		delete req;
-		return false;
-	}
-	return true;
-}
-
-bool IoUringBackend::enqueueRequest(AsyncRequest *req, void *buffer, DWORD length, const std::optional<off64_t> &offset,
-									bool isWrite) {
-	std::unique_lock lock(mSubmitMutex);
-	if (!mRunning.load(std::memory_order_acquire) && req->kind != AsyncRequest::Kind::Shutdown) {
-		return false;
-	}
-
-	struct io_uring_sqe *sqe;
-	while (true) {
-		sqe = io_uring_get_sqe(&mRing);
-		if (!sqe) {
-			mQueueCv.wait(lock);
-			if (!mRunning.load(std::memory_order_acquire) && req->kind != AsyncRequest::Kind::Shutdown) {
-				return false;
-			}
-			continue;
-		}
-		io_uring_sqe_set_data(sqe, req);
-		if (req->kind == AsyncRequest::Kind::Shutdown) {
-			io_uring_prep_nop(sqe);
-		} else {
-			req->vec.iov_base = buffer;
-			req->vec.iov_len = length;
-			off64_t fileOffset = -1;
-			if (!req->isPipe && offset.has_value()) {
-				fileOffset = *offset;
-			}
-			int fd = req->file ? req->file->fd : -1;
-			if (isWrite) {
-				io_uring_prep_writev(sqe, fd, &req->vec, 1, fileOffset);
-			} else {
-				io_uring_prep_readv(sqe, fd, &req->vec, 1, fileOffset);
-			}
-		}
-		mPending.fetch_add(1, std::memory_order_relaxed);
-		break;
-	}
-
-	while (true) {
-		int res = io_uring_submit(&mRing);
-		if (res >= 0) {
-			break;
-		} else if (res == -EINTR) {
-			continue;
-		} else if (res == -EBUSY || res == -EAGAIN) {
-			lock.unlock();
-			std::this_thread::yield();
-			lock.lock();
-			continue;
-		}
-		DEBUG_LOG("io_uring_submit failed (will retry): %d\n", res);
-	}
-
-	lock.unlock();
-	mQueueCv.notify_one();
-	return true;
-}
-
-void IoUringBackend::requestStop() {
-	mRunning.store(false, std::memory_order_release);
-	auto *req = new AsyncRequest{AsyncRequest::Kind::Shutdown, Pin<kernel32::FileObject>{}, nullptr, false};
-	if (!enqueueRequest(req, nullptr, 0, std::nullopt, false)) {
-		delete req;
-	}
-}
-
-void IoUringBackend::workerLoop() {
-	while (mRunning.load(std::memory_order_acquire) || mPending.load(std::memory_order_acquire) > 0) {
-		struct io_uring_cqe *cqe = nullptr;
-		int ret = io_uring_wait_cqe(&mRing, &cqe);
-		if (ret == -EINTR) {
-			continue;
-		}
-		if (ret < 0) {
-			DEBUG_LOG("io_uring_wait_cqe failed: %d\n", ret);
-			continue;
-		}
-		handleCompletion(cqe);
-		io_uring_cqe_seen(&mRing, cqe);
-		notifySpace();
-	}
-
-	while (mPending.load(std::memory_order_acquire) > 0) {
-		struct io_uring_cqe *cqe = nullptr;
-		int ret = io_uring_peek_cqe(&mRing, &cqe);
-		if (ret != 0 || !cqe) {
-			break;
-		}
-		handleCompletion(cqe);
-		io_uring_cqe_seen(&mRing, cqe);
-		notifySpace();
-	}
-}
-
-void IoUringBackend::handleCompletion(struct io_uring_cqe *cqe) {
-	auto *req = static_cast<AsyncRequest *>(io_uring_cqe_get_data(cqe));
-	if (!req) {
-		return;
-	}
-
-	if (req->kind == AsyncRequest::Kind::Shutdown) {
-		delete req;
-		mPending.fetch_sub(1, std::memory_order_acq_rel);
-		return;
-	}
-
-	OVERLAPPED *ov = req->overlapped;
-	if (ov) {
-		if (cqe->res >= 0) {
-			ov->InternalHigh = static_cast<ULONG_PTR>(cqe->res);
-			if (req->kind == AsyncRequest::Kind::Read && cqe->res == 0) {
-				ov->Internal = req->isPipe ? STATUS_PIPE_BROKEN : STATUS_END_OF_FILE;
-			} else {
-				ov->Internal = STATUS_SUCCESS;
-			}
-		} else {
-			int err = -cqe->res;
-			ov->InternalHigh = 0;
-			if (err == EPIPE) {
-				ov->Internal = STATUS_PIPE_BROKEN;
-			} else {
-				NTSTATUS status = wibo::statusFromErrno(err);
-				if (status == STATUS_SUCCESS) {
-					status = STATUS_UNEXPECTED_IO_ERROR;
-				}
-				ov->Internal = status;
-			}
-		}
-		kernel32::detail::signalOverlappedEvent(ov);
-	}
-
-	delete req;
-	mPending.fetch_sub(1, std::memory_order_acq_rel);
-}
-
-void IoUringBackend::notifySpace() {
-	std::lock_guard lk(mSubmitMutex);
-	mQueueCv.notify_all();
-}
-
-} // namespace async_io
+} // namespace wibo
diff --git a/src/async_io.h b/src/async_io.h
index c922ec8..4674b37 100644
--- a/src/async_io.h
+++ b/src/async_io.h
@@ -5,15 +5,28 @@
 
 #include <optional>
 
-namespace async_io {
+namespace wibo {
 
-bool initialize();
-void shutdown();
-bool running();
+class AsyncIOBackend {
+  public:
+	virtual ~AsyncIOBackend() = default;
+	virtual bool init() = 0;
+	virtual void shutdown() = 0;
+	[[nodiscard]] virtual bool running() const noexcept = 0;
+	virtual bool queueRead(Pin<kernel32::FileObject> file, OVERLAPPED *ov, void *buffer, DWORD length,
+						   const std::optional<off_t> &offset, bool isPipe) = 0;
+	virtual bool queueWrite(Pin<kernel32::FileObject> file, OVERLAPPED *ov, const void *buffer, DWORD length,
+							const std::optional<off_t> &offset, bool isPipe) = 0;
+};
 
-bool queueRead(Pin<kernel32::FileObject> file, OVERLAPPED *ov, void *buffer, DWORD length,
-			   const std::optional<off64_t> &offset, bool isPipe);
-bool queueWrite(Pin<kernel32::FileObject> file, OVERLAPPED *ov, const void *buffer, DWORD length,
-				const std::optional<off64_t> &offset, bool isPipe);
+namespace detail {
 
-} // namespace async_io
+#if WIBO_ENABLE_LIBURING
+std::unique_ptr<AsyncIOBackend> createIoUringBackend();
+#endif
+
+} // namespace detail
+
+AsyncIOBackend &asyncIO();
+
+} // namespace wibo
diff --git a/src/async_io_uring.cpp b/src/async_io_uring.cpp
new file mode 100644
index 0000000..b319e7d
--- /dev/null
+++ b/src/async_io_uring.cpp
@@ -0,0 +1,244 @@
+#include "async_io.h"
+
+#include "errors.h"
+#include "kernel32/internal.h"
+#include "kernel32/overlapped_util.h"
+
+#include <liburing.h>
+#include <optional>
+
+namespace {
+
+constexpr unsigned kQueueDepth = 64;
+
+struct AsyncRequest {
+	enum class Kind { Read, Write, Shutdown };
+
+	Kind kind;
+	Pin<kernel32::FileObject> file;
+	OVERLAPPED *overlapped = nullptr;
+	bool isPipe = false;
+	struct iovec vec{};
+};
+
+class IoUringBackend : public wibo::AsyncIOBackend {
+  public:
+	~IoUringBackend() override { shutdown(); }
+	bool init() override;
+	void shutdown() override;
+	[[nodiscard]] bool running() const noexcept override { return mRunning.load(std::memory_order_acquire); }
+
+	bool queueRead(Pin<kernel32::FileObject> file, OVERLAPPED *ov, void *buffer, DWORD length,
+				   const std::optional<off_t> &offset, bool isPipe) override;
+	bool queueWrite(Pin<kernel32::FileObject> file, OVERLAPPED *ov, const void *buffer, DWORD length,
+					const std::optional<off_t> &offset, bool isPipe) override;
+
+  private:
+	bool enqueueRequest(AsyncRequest *req, void *buffer, DWORD length, const std::optional<off_t> &offset,
+						bool isWrite);
+	void requestStop();
+	void workerLoop();
+	void handleCompletion(struct io_uring_cqe *cqe);
+	void notifySpace();
+
+	struct io_uring mRing{};
+	std::mutex mSubmitMutex;
+	std::condition_variable mQueueCv;
+	std::atomic<bool> mRunning{false};
+	std::atomic<uint32_t> mPending{0};
+	std::thread mThread;
+};
+
+bool IoUringBackend::init() {
+	if (mRunning.load(std::memory_order_acquire)) {
+		return true;
+	}
+	int rc = io_uring_queue_init(kQueueDepth, &mRing, 0);
+	if (rc < 0) {
+		DEBUG_LOG("io_uring_queue_init failed: %d\n", rc);
+		return false;
+	}
+	mRunning.store(true, std::memory_order_release);
+	mThread = std::thread(&IoUringBackend::workerLoop, this);
+	DEBUG_LOG("io_uring backend initialized (depth=%u)\n", kQueueDepth);
+	return true;
+}
+
+void IoUringBackend::shutdown() {
+	if (!mRunning.exchange(false, std::memory_order_acq_rel)) {
+		return;
+	}
+	requestStop();
+	if (mThread.joinable()) {
+		mThread.join();
+	}
+	io_uring_queue_exit(&mRing);
+}
+
+bool IoUringBackend::queueRead(Pin<kernel32::FileObject> file, OVERLAPPED *ov, void *buffer, DWORD length,
+							   const std::optional<off_t> &offset, bool isPipe) {
+	auto *req = new AsyncRequest{AsyncRequest::Kind::Read, std::move(file), ov, isPipe};
+	if (!enqueueRequest(req, buffer, length, offset, false)) {
+		delete req;
+		return false;
+	}
+	return true;
+}
+
+bool IoUringBackend::queueWrite(Pin<kernel32::FileObject> file, OVERLAPPED *ov, const void *buffer, DWORD length,
+								const std::optional<off_t> &offset, bool isPipe) {
+	auto *req = new AsyncRequest{AsyncRequest::Kind::Write, std::move(file), ov, isPipe};
+	if (!enqueueRequest(req, const_cast<void *>(buffer), length, offset, true)) {
+		delete req;
+		return false;
+	}
+	return true;
+}
+
+bool IoUringBackend::enqueueRequest(AsyncRequest *req, void *buffer, DWORD length, const std::optional<off_t> &offset,
+									bool isWrite) {
+	std::unique_lock lock(mSubmitMutex);
+	if (!mRunning.load(std::memory_order_acquire) && req->kind != AsyncRequest::Kind::Shutdown) {
+		return false;
+	}
+
+	struct io_uring_sqe *sqe;
+	while (true) {
+		sqe = io_uring_get_sqe(&mRing);
+		if (!sqe) {
+			mQueueCv.wait(lock);
+			if (!mRunning.load(std::memory_order_acquire) && req->kind != AsyncRequest::Kind::Shutdown) {
+				return false;
+			}
+			continue;
+		}
+		io_uring_sqe_set_data(sqe, req);
+		if (req->kind == AsyncRequest::Kind::Shutdown) {
+			io_uring_prep_nop(sqe);
+		} else {
+			req->vec.iov_base = buffer;
+			req->vec.iov_len = length;
+			off_t fileOffset = -1;
+			if (!req->isPipe && offset.has_value()) {
+				fileOffset = *offset;
+			}
+			int fd = req->file ? req->file->fd : -1;
+			if (isWrite) {
+				io_uring_prep_writev(sqe, fd, &req->vec, 1, fileOffset);
+			} else {
+				io_uring_prep_readv(sqe, fd, &req->vec, 1, fileOffset);
+			}
+		}
+		mPending.fetch_add(1, std::memory_order_relaxed);
+		break;
+	}
+
+	while (true) {
+		int res = io_uring_submit(&mRing);
+		if (res >= 0) {
+			break;
+		} else if (res == -EINTR) {
+			continue;
+		} else if (res == -EBUSY || res == -EAGAIN) {
+			lock.unlock();
+			std::this_thread::yield();
+			lock.lock();
+			continue;
+		}
+		DEBUG_LOG("io_uring_submit failed (will retry): %d\n", res);
+	}
+
+	lock.unlock();
+	mQueueCv.notify_one();
+	return true;
+}
+
+void IoUringBackend::requestStop() {
+	mRunning.store(false, std::memory_order_release);
+	auto *req = new AsyncRequest{AsyncRequest::Kind::Shutdown, Pin<kernel32::FileObject>{}, nullptr, false};
+	if (!enqueueRequest(req, nullptr, 0, std::nullopt, false)) {
+		delete req;
+	}
+}
+
+void IoUringBackend::workerLoop() {
+	while (mRunning.load(std::memory_order_acquire) || mPending.load(std::memory_order_acquire) > 0) {
+		struct io_uring_cqe *cqe = nullptr;
+		int ret = io_uring_wait_cqe(&mRing, &cqe);
+		if (ret == -EINTR) {
+			continue;
+		}
+		if (ret < 0) {
+			DEBUG_LOG("io_uring_wait_cqe failed: %d\n", ret);
+			continue;
+		}
+		handleCompletion(cqe);
+		io_uring_cqe_seen(&mRing, cqe);
+		notifySpace();
+	}
+
+	while (mPending.load(std::memory_order_acquire) > 0) {
+		struct io_uring_cqe *cqe = nullptr;
+		int ret = io_uring_peek_cqe(&mRing, &cqe);
+		if (ret != 0 || !cqe) {
+			break;
+		}
+		handleCompletion(cqe);
+		io_uring_cqe_seen(&mRing, cqe);
+		notifySpace();
+	}
+}
+
+void IoUringBackend::handleCompletion(struct io_uring_cqe *cqe) {
+	auto *req = static_cast<AsyncRequest *>(io_uring_cqe_get_data(cqe));
+	if (!req) {
+		return;
+	}
+
+	if (req->kind == AsyncRequest::Kind::Shutdown) {
+		delete req;
+		mPending.fetch_sub(1, std::memory_order_acq_rel);
+		return;
+	}
+
+	OVERLAPPED *ov = req->overlapped;
+	if (ov) {
+		if (cqe->res >= 0) {
+			ov->InternalHigh = static_cast<ULONG_PTR>(cqe->res);
+			if (req->kind == AsyncRequest::Kind::Read && cqe->res == 0) {
+				ov->Internal = req->isPipe ? STATUS_PIPE_BROKEN : STATUS_END_OF_FILE;
+			} else {
+				ov->Internal = STATUS_SUCCESS;
+			}
+		} else {
+			int err = -cqe->res;
+			ov->InternalHigh = 0;
+			if (err == EPIPE) {
+				ov->Internal = STATUS_PIPE_BROKEN;
+			} else {
+				NTSTATUS status = wibo::statusFromErrno(err);
+				if (status == STATUS_SUCCESS) {
+					status = STATUS_UNEXPECTED_IO_ERROR;
+				}
+				ov->Internal = status;
+			}
+		}
+		kernel32::detail::signalOverlappedEvent(ov);
+	}
+
+	delete req;
+	mPending.fetch_sub(1, std::memory_order_acq_rel);
+}
+
+void IoUringBackend::notifySpace() {
+	std::lock_guard lk(mSubmitMutex);
+	mQueueCv.notify_all();
+}
+
+} // namespace
+
+namespace wibo::detail {
+
+std::unique_ptr<AsyncIOBackend> createIoUringBackend() { return std::make_unique<IoUringBackend>(); }
+
+} // namespace wibo::detail
diff --git a/src/common.h b/src/common.h
index 9fab80f..744f8c1 100644
--- a/src/common.h
+++ b/src/common.h
@@ -13,11 +13,7 @@
 
 // On Windows, the incoming stack is aligned to a 4 byte boundary.
 // force_align_arg_pointer will realign the stack to match GCC's 16 byte alignment.
-#ifdef __clang__
-#define WIN_ENTRY __attribute__((force_align_arg_pointer))
-#else
-#define WIN_ENTRY __attribute__((force_align_arg_pointer, callee_pop_aggregate_return(0)))
-#endif
+#define WIN_ENTRY __attribute__((ms_abi, force_align_arg_pointer))
 #define WIN_FUNC WIN_ENTRY __attribute__((stdcall))
 
 #define DEBUG_LOG(...)                                                                                                 \
diff --git a/src/files.cpp b/src/files.cpp
index 4bc575b..efdc0fd 100644
--- a/src/files.cpp
+++ b/src/files.cpp
@@ -142,7 +142,7 @@ std::string pathToWindows(const std::filesystem::path &path) {
 	return str;
 }
 
-IOResult read(FileObject *file, void *buffer, size_t bytesToRead, const std::optional<off64_t> &offset,
+IOResult read(FileObject *file, void *buffer, size_t bytesToRead, const std::optional<off_t> &offset,
 			  bool updateFilePointer) {
 	IOResult result{};
 	if (!file || !file->valid()) {
@@ -180,13 +180,13 @@ IOResult read(FileObject *file, void *buffer, size_t bytesToRead, const std::opt
 		return result;
 	}
 
-	const auto doRead = [&](off64_t pos) {
+	const auto doRead = [&](off_t pos) {
 		size_t total = 0;
 		size_t remaining = bytesToRead;
 		uint8_t *in = static_cast<uint8_t *>(buffer);
 		while (remaining > 0) {
 			size_t chunk = remaining > SSIZE_MAX ? SSIZE_MAX : remaining;
-			ssize_t rc = pread64(file->fd, in + total, chunk, pos);
+			ssize_t rc = pread(file->fd, in + total, chunk, pos);
 			if (rc == -1) {
 				if (errno == EINTR) {
 					continue;
@@ -207,10 +207,10 @@ IOResult read(FileObject *file, void *buffer, size_t bytesToRead, const std::opt
 
 	if (updateFilePointer || !offset.has_value()) {
 		std::lock_guard lk(file->m);
-		const off64_t pos = offset.value_or(file->filePos);
+		const off_t pos = offset.value_or(file->filePos);
 		doRead(pos);
 		if (updateFilePointer) {
-			file->filePos = pos + static_cast<off64_t>(result.bytesTransferred);
+			file->filePos = pos + static_cast<off_t>(result.bytesTransferred);
 		}
 	} else {
 		doRead(*offset);
@@ -219,7 +219,7 @@ IOResult read(FileObject *file, void *buffer, size_t bytesToRead, const std::opt
 	return result;
 }
 
-IOResult write(FileObject *file, const void *buffer, size_t bytesToWrite, const std::optional<off64_t> &offset,
+IOResult write(FileObject *file, const void *buffer, size_t bytesToWrite, const std::optional<off_t> &offset,
 			   bool updateFilePointer) {
 	IOResult result{};
 	if (!file || !file->valid()) {
@@ -256,7 +256,7 @@ IOResult write(FileObject *file, const void *buffer, size_t bytesToWrite, const
 		}
 		result.bytesTransferred = total;
 		if (updateFilePointer) {
-			off64_t pos = file->isPipe ? 0 : lseek64(file->fd, 0, SEEK_CUR);
+			off_t pos = file->isPipe ? 0 : lseek(file->fd, 0, SEEK_CUR);
 			if (pos >= 0) {
 				file->filePos = pos;
 			} else if (result.unixError == 0) {
@@ -266,13 +266,13 @@ IOResult write(FileObject *file, const void *buffer, size_t bytesToWrite, const
 		return result;
 	}
 
-	auto doWrite = [&](off64_t pos) {
+	auto doWrite = [&](off_t pos) {
 		size_t total = 0;
 		size_t remaining = bytesToWrite;
 		const uint8_t *in = static_cast<const uint8_t *>(buffer);
 		while (remaining > 0) {
 			size_t chunk = remaining > SSIZE_MAX ? SSIZE_MAX : remaining;
-			ssize_t rc = pwrite64(file->fd, in + total, chunk, pos);
+			ssize_t rc = pwrite(file->fd, in + total, chunk, pos);
 			if (rc == -1) {
 				if (errno == EINTR) {
 					continue;
@@ -292,10 +292,10 @@ IOResult write(FileObject *file, const void *buffer, size_t bytesToWrite, const
 
 	if (updateFilePointer || !offset.has_value()) {
 		std::lock_guard lk(file->m);
-		const off64_t pos = offset.value_or(file->filePos);
+		const off_t pos = offset.value_or(file->filePos);
 		doWrite(pos);
 		if (updateFilePointer) {
-			file->filePos = pos + static_cast<off64_t>(result.bytesTransferred);
+			file->filePos = pos + static_cast<off_t>(result.bytesTransferred);
 		}
 	} else {
 		doWrite(*offset);
diff --git a/src/files.h b/src/files.h
index efe195b..df1c73d 100644
--- a/src/files.h
+++ b/src/files.h
@@ -21,9 +21,9 @@ struct IOResult {
 void init();
 std::filesystem::path pathFromWindows(const char *inStr);
 std::string pathToWindows(const std::filesystem::path &path);
-IOResult read(FileObject *file, void *buffer, size_t bytesToRead, const std::optional<off64_t> &offset,
+IOResult read(FileObject *file, void *buffer, size_t bytesToRead, const std::optional<off_t> &offset,
 			  bool updateFilePointer);
-IOResult write(FileObject *file, const void *buffer, size_t bytesToWrite, const std::optional<off64_t> &offset,
+IOResult write(FileObject *file, const void *buffer, size_t bytesToWrite, const std::optional<off_t> &offset,
 			   bool updateFilePointer);
 HANDLE getStdHandle(DWORD nStdHandle);
 BOOL setStdHandle(DWORD nStdHandle, HANDLE hHandle);
diff --git a/src/main.cpp b/src/main.cpp
index 4099a3b..dc8a439 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,5 +1,5 @@
-#include "common.h"
 #include "async_io.h"
+#include "common.h"
 #include "context.h"
 #include "files.h"
 #include "modules.h"
@@ -408,14 +408,13 @@ int main(int argc, char **argv) {
 
 	blockUpper2GB();
 	files::init();
-	wibo::processes().init();
-	async_io::initialize();
 
 	// Create TIB
 	memset(&tib, 0, sizeof(tib));
 	tib.tib = &tib;
-	tib.peb = (PEB *)calloc(sizeof(PEB), 1);
-	tib.peb->ProcessParameters = (RTL_USER_PROCESS_PARAMETERS *)calloc(sizeof(RTL_USER_PROCESS_PARAMETERS), 1);
+	tib.peb = static_cast<PEB *>(calloc(1, sizeof(PEB)));
+	tib.peb->ProcessParameters =
+		static_cast<RTL_USER_PROCESS_PARAMETERS *>(calloc(1, sizeof(RTL_USER_PROCESS_PARAMETERS)));
 	wibo::processPeb = tib.peb;
 	wibo::initializeTibStackInfo(&tib);
 	if (!wibo::installTibForCurrentThread(&tib)) {
diff --git a/src/processes.cpp b/src/processes.cpp
index 14eaeb5..f636c4f 100644
--- a/src/processes.cpp
+++ b/src/processes.cpp
@@ -74,6 +74,7 @@ bool ProcessManager::init() {
 
 	mRunning.store(true, std::memory_order_release);
 	mThread = std::thread(&ProcessManager::runLoop, this);
+	DEBUG_LOG("ProcessManager initialized\n");
 	return true;
 }
 
@@ -159,7 +160,7 @@ void ProcessManager::wake() const {
 		return;
 	}
 	uint64_t n = 1;
-	write(mWakeFd, &n, sizeof(n));
+	ssize_t r [[maybe_unused]] = write(mWakeFd, &n, sizeof(n));
 }
 
 void ProcessManager::checkPidfd(int pidfd) {
@@ -212,6 +213,10 @@ void ProcessManager::checkPidfd(int pidfd) {
 
 ProcessManager &processes() {
 	static ProcessManager mgr;
+	if (!mgr.init()) {
+		fprintf(stderr, "Failed to initialize ProcessManager\n");
+		abort();
+	}
 	return mgr;
 }
 
diff --git a/src/resources.cpp b/src/resources.cpp
index 3b8a35c..f7319ee 100644
--- a/src/resources.cpp
+++ b/src/resources.cpp
@@ -99,9 +99,8 @@ const wibo::ImageResourceDataEntry *entryAsData(const uint8_t *base, const Image
 
 uint16_t primaryLang(uint16_t lang) { return lang & 0x3FFu; }
 
-const ImageResourceDirectoryEntry *selectLanguageEntry(const ImageResourceDirectory *dir, const uint8_t *base,
-													   uint32_t rsrcSize, std::optional<uint16_t> desired,
-													   uint16_t &chosenLang) {
+const ImageResourceDirectoryEntry *selectLanguageEntry(const ImageResourceDirectory *dir,
+													   std::optional<uint16_t> desired, uint16_t &chosenLang) {
 	const auto *entries = resourceEntries(dir);
 	uint16_t total = dir->numberOfNamedEntries + dir->numberOfIdEntries;
 	const ImageResourceDirectoryEntry *primaryMatch = nullptr;
@@ -172,7 +171,7 @@ bool Executable::findResource(const ResourceIdentifier &type, const ResourceIden
 		return false;
 	}
 	uint16_t chosenLang = language.value_or(0);
-	const auto *langEntry = selectLanguageEntry(langDir, base, rsrcSize, language, chosenLang);
+	const auto *langEntry = selectLanguageEntry(langDir, language, chosenLang);
 	if (!langEntry) {
 		wibo::lastError = ERROR_RESOURCE_LANG_NOT_FOUND;
 		return false;