ftell() in C with example

ftell() in C is used to find out the position of the file pointer in the file with respect to starting of the file.

Syntax

The syntax of ftell() is:

long ftell(FILE *stream);

Parameters

• stream: It is the pointer to the file stream.

Return Value

• It returns a long integer value as the current position in the file.
• It returns -1 if an error occurs.

Example of ftell()

The below C program demonstrates the use of ftell() function.

C

// C program to demonstrate use of ftell()
#include <stdio.h>

int main()
{
    /* Opening file in read mode */
    FILE* fp = fopen("g4g.txt", "r");

    /* Reading first string */
    char string[20];
    fscanf(fp, "%s", string);

    /* Printing position of file pointer */
    printf("%ld", ftell(fp));
    return 0;
}

Suppose the file g4g.txt contains the following data:

g4g.txt

Someone over there is calling you. We are going for work. Take care of yourself.

Output

7

Explanation

ftell(fp) returns 7. As the length of “someone” is 7 and the character indices are from 0 to 6.

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