Header File 

io.h  

Category 

Input/output Routines 

Prototype 

long tell(int handle); 

Description 

Gets the current position of a file pointer. 

tell gets the current position of the file pointer associated with handle and expresses it as the number of bytes from the beginning of the file. 

Return Value 

tell returns the current file pointer position. A return of -1 (long) indicates an error, and the global variable errno is set to

Example

#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <io.h>
int main(void)
{
   int handle;
   char msg[] = "Hello world";
   if ((handle = open("TEST.$$$", O_CREAT | O_TEXT | O_APPEND)) == -1)
   {
      perror("Error:");
      return 1;
   }
   write(handle, msg, strlen(msg));
   printf("The file pointer is at byte %ld\n", tell(handle));
   close(handle);
   return 0;
}

Portability