_fileno
Visual Studio .NET 2003
Gets the file descriptor associated with a stream.
int _fileno( FILE *stream );
Parameter
- stream
- Pointer to FILE structure.
Return Value
_fileno returns the file descriptor. There is no error return. The result is undefined if stream does not specify an open file.
Remarks
The _fileno routine returns the file descriptor currently associated with stream. This routine is implemented both as a function and as a macro. For details on choosing either implementation, see Choosing Between Functions and Macros.
Requirements
| Function | Required header | Compatibility |
|---|---|---|
| _fileno | <stdio.h> | Win 98, Win Me, Win NT, Win 2000, Win XP |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
All versions of the C run-time libraries.
Example
// crt_fileno.c
/* This program uses _fileno to obtain
* the file descriptor for some standard C streams.
*/
#include <stdio.h>
int main( void )
{
printf( "The file descriptor for stdin is %d\n", _fileno( stdin ) );
printf( "The file descriptor for stdout is %d\n", _fileno( stdout ) );
printf( "The file descriptor for stderr is %d\n", _fileno( stderr ) );
}
Output
The file descriptor for stdin is 0 The file descriptor for stdout is 1 The file descriptor for stderr is 2
See Also
Stream I/O Routines | _fdopen | _filelength | fopen | freopen | Run-Time Routines and .NET Framework Equivalents
