为文件 I/O 操作设置默认文件转换模式。Sets the default file translation mode for file I/O operations.


errno_t _set_fmode(
   int mode


需要文件转换模式: _O_TEXT_O_BINARYThe file translation mode desired: _O_TEXT or _O_BINARY.

返回值Return Value

如果成功,则返回零;如果失败,则返回错误代码。Returns zero if successful, an error code on failure. 如果mode不是 _O_TEXT_O_BINARY_O_WTEXT,则会调用无效参数处理程序,如参数验证中所述。If mode is not _O_TEXT or _O_BINARY or _O_WTEXT, the invalid parameter handler is invoked, as described in Parameter Validation. 如果允许执行继续,则此函数会将errno设置为EINVAL并返回EINVALIf execution is allowed to continue, this function sets errno to EINVAL and returns EINVAL.


该函数设置 _fmode 全局变量。The function sets the _fmode global variable. 此变量为文件 i/o 操作 _open_pipe指定默认文件转换模式。This variable specifies the default file translation mode for the file I/O operations _open and _pipe.

_O_TEXT_O_BINARY是在 fcntl.h> 中定义的。_O_TEXT and _O_BINARY are defined in Fcntl.h. EINVAL是在 Errno 中定义的。EINVAL is defined in Errno.h.


例程所返回的值Routine 必需的标头Required header 可选标头Optional header
_set_fmode_set_fmode <stdlib.h><stdlib.h> <fcntl.h>、<errno.h><fcntl.h>, <errno.h>

有关更多兼容性信息,请参阅 兼容性For more compatibility information, see Compatibility.


// crt_set_fmode.c
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>     /* for _O_TEXT and _O_BINARY */
#include <errno.h>     /* for EINVAL */
#include <sys\stat.h>  /* for _S_IWRITE */
#include <share.h>     /* for _SH_DENYNO */

int main()
   int mode, fd, ret;
   errno_t err;
   int buf[12] = { 65, 66, 67, 68, 69, 70, 71, 72, 73, 74,
                   75, 76 };
   char * filename = "fmode.out";

   err = _get_fmode(&mode);
   if (err == EINVAL)
      printf( "Invalid parameter: mode\n");
      return 1;
      printf( "Default Mode is %s\n", mode == _O_TEXT ? "text" :

   err = _set_fmode(_O_BINARY);
   if (err == EINVAL)
      printf( "Invalid mode.\n");
      return 1;

   if ( _sopen_s(&fd, filename, _O_RDWR | _O_CREAT, _SH_DENYNO, _S_IWRITE | _S_IREAD) != 0 )
      printf( "Error opening the file %s\n", filename);
      return 1;

   if (ret = _write(fd, buf, 12*sizeof(int)) < 12*sizeof(int))
      printf( "Problem writing to the file %s.\n", filename);
      printf( "Number of bytes written: %d\n", ret);

   if (_close(fd) != 0)
      printf("Error closing the file %s. Error code %d.\n",
             filename, errno);

   system("type fmode.out");
Default Mode is binary
A   B   C   D   E   F   G   H   I   J   K   L

请参阅See also

文本和二进制模式文件 I/OText and Binary Mode File I/O