prime/src/Runtime/wchar_io.c

#include <stdio.h>

int fwide(FILE* stream, int mode) {
  int orientation;
  int result;

  if ((stream == NULL) || (stream->mode.file_kind == __closed_file))
    return 0;
  orientation = stream->mode.file_orientation;
  switch (orientation) {
  case __unoriented:
    if (mode > 0)
      stream->mode.file_orientation = __wide_oriented;
    else if (mode < 0)
      stream->mode.file_orientation = __char_oriented;
    result = mode;
    break;

  case __wide_oriented:
    result = 1;
    break;

  case __char_oriented:
    result = -1;
    break;
  }
  return result;
}