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_tell, _telli64

Get the position of the file pointer.


long _tell(
   int handle
);
__int64 _telli64(
   int handle 
);

Parameters

handle

File descriptor referring to open file.

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.

The _tell function gets the current position of the file pointer (if any) associated with the handle argument. The position is expressed as the number of bytes from the beginning of the file. For the _telli64 function, this value is expressed as a 64-bit integer.

Routine Required header Compatibility

_tell, _telli64

<io.h>

Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003

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 );
}

Line one.
Line two.

Output

Current file position is: 20

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