Header File 

stdio.h  

Category 

Input/output Routines 

Prototype 

long int ftell(FILE *stream); 

Description 

Returns the current file pointer. 

ftell returns the current file pointer for stream. The offset is measured in bytes from the beginning of the file (if the file is binary). The value returned by ftell can be used in a subsequent call to fseek. 

Return Value 

ftell returns the current file pointer position on success. It returns -1L on error and sets the global variable errno to a positive value. 

In the event of an error return the global variable errno is set to one of the following values:

Example

#include <stdio.h>
int main(void)
{
   FILE *stream;
   stream = fopen("MYFILE.TXT", "w+");
   fprintf(stream, "This is a test");
   printf("The file pointer is at byte %ld\n", ftell(stream));
   fclose(stream);
   return 0;
}

Portability