_tell - Get Pointer Position

Syntax

#include <io.h>
long _tell(int handle);

tell gets the current position of the file pointer associated with handle. The position is the number of bytes from the beginning of the file.

tell returns the current position. A return value of -1L indicates an error, and errno is set to one of the following values: compact break=fit.
Value
EBADF
EOS2ERR
On devices incapable of seeking (such as screens and printers), the return value is -1L.

This example opens the file tell.dat. It then calls _tell to get the current position of the file pointer and report whether the operation is successful. The program then closes tell.dat.

#include <io.h>#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>

#define FILENAME  "tell.dat"

int main(void)
{
   long filePtrPos;
   int fh;

   printf("Creating file.\n");
   system("echo Sample Program > " FILENAME);
   if (-1 == (fh = open(FILENAME, O_RDWR|O_APPEND))) {
      perror("Unable to open " FILENAME);
      remove(FILENAME);
      return EXIT_FAILURE;
   }
   /* Get the current file pointer position.                                 */
   if (-1 == (filePtrPos = _tell(fh))) {
      perror("Unable to tell");
      close(fh);
      remove(FILENAME);
      return EXIT_FAILURE;
   }
   printf("File pointer is at position %d.\n", filePtrPos);
   close(fh);
   remove(FILENAME);
   return 0;

   /****************************************************************************
      The output should be:

      Creating file.
      File pointer is at position 0.
   ****************************************************************************/
}

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