Get information about an open file.

int _fstat( 
   int fd,
   struct _stat *buffer 
);
int _fstat64( 
   int fd,
   struct __stat64 *buffer 
);
int _fstati64( 
   int fd,
   struct _stati64 *buffer 
);

Parameters

fd

File descriptor of open file.

buffer

Pointer to structure to store results.

Return Value

Return 0 if the file-status information is obtained. A return value of –1 indicates an error, in which case errno is set to EBADF, indicating an invalid file descriptor.

Remarks

The _fstat function obtains information about the open file associated with fd and stores it in the structure pointed to by buffer. The _stat structure, defined in SYS\STAT.H, contains the following fields:

st_atime

Time of last file access.

st_ctime

Time of creation of file.

st_dev

If a device, fd; otherwise 0.

st_mode

Bit mask for file-mode information. The _S_IFCHR bit is set if fd refers to a device. The _S_IFREG bit is set if fd refers to an ordinary file. The read/write bits are set according to the file's permission mode. _S_IFCHR and other constants are defined in SYS\STAT.H.

st_mtime

Time of last modification of file.

st_nlink

Always 1 on non-NTFS file systems.

st_rdev

If a device, fd; otherwise 0.

st_size

Size of the file in bytes.

If fd refers to a device, the st_atime, st_ctime, st_mtime, and st_size fields are not meaningful.

Because STAT.H uses the _dev_t type, which is defined in TYPES.H, you must include TYPES.H before STAT.H in your code.

_fstat64, which uses the __stat64 structure, allows file-creation dates to be expressed up through 23:59:59, December 31, 3000, UTC, whereas the other functions only represent dates through 19:14:07 January 18, 2038, UTC. Midnight, January 1, 1970, is the lower bound of the date range for all these functions.

Requirements

For additional compatibility information, see Compatibility in the Introduction.

Libraries

All versions of the C run-time libraries.

Example

// crt_fstat.c
/* This program uses _fstat64 to report
 * the size of a file named F_STAT.OUT.
 */

#include <io.h>
#include <fcntl.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main( void )
{
   struct __stat64 buf;
   int fd, result;
   char buffer[] = "A line to output";

   if( (fd = _open( "f_stat.out", _O_CREAT | _O_WRONLY |
                                  _O_TRUNC )) ==  -1 )
   _write( fd, buffer, strlen( buffer ) );

   /* Get data associated with "fd": */
   result = _fstat64( fd, &buf );

   /* Check if statistics are valid: */
   if( result != 0 )
      printf( "Bad file file descriptor\n" );
   else
   {
      printf( "File size     : %ld\n", buf.st_size );

      printf( "Time modified : %s", _ctime64( &buf.st_ctime ) );
   }
   _close( fd );
}

Sample Output

File size     : 0
Time modified : Wed Feb 13 09:00:01 2002

See Also

File Handling Routines | _access | _chmod | _filelength | _stat | Run-Time Routines and .NET Framework Equivalents