_tell, _telli64
Visual Studio 2008
Get the position of the file pointer.
long _tell( int handle ); __int64 _telli64( int handle );
The current position of the file pointer. On devices incapable of seeking, the return value is undefined.
A return value of –1L indicates an error. If handle is an invalid file descriptor, the invalid parameter handler is invoked, as described in Parameter Validation. If execution is allowed to continue, these functions set errno to EBADF and return -1L.
See _doserrno, errno, _sys_errlist, and _sys_nerr for more information on this, and other, return codes.
|
Routine |
Required header |
|---|---|
|
_tell , _telli64 |
<io.h> |
For additional compatibility information, see Compatibility in the Introduction.
// crt_tell.c
// This program uses _tell to tell the
// file pointer position after a file read.
//
#include <io.h>
#include <stdio.h>
#include <fcntl.h>
#include <share.h>
#include <string.h>
int main( void )
{
int fh;
char buffer[500];
if ( _sopen_s( &fh, "crt_tell.txt", _O_RDONLY, _SH_DENYNO, 0) )
{
char buff[50];
_strerror_s( buff, sizeof(buff), NULL );
printf( buff );
exit( -1 );
}
if( _read( fh, buffer, 500 ) > 0 )
printf( "Current file position is: %d\n", _tell( fh ) );
_close( fh );
}
