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

  Meaning
  EBADF
  The file handle is not valid.
  EOS2ERR
  The call to the operating system was not successful.

  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.
   ****************************************************************************/
}

• fseek
  
• ftell
  
• lseek

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