fseek() vs rewind() in C

In C, the functions fseek() and rewind() helps in manipulating the position of the pointer in the opened file but serve different purposes and have distinct working. The below table lists the major differences between fseek() and rewind() in C:

Which should be preferred?

In C, fseek() should be preferred over rewind() even if we want to move to the beginning of the file. It is due to the better error handling by fseek() as compared to the rewind() function.

Let's take a look at the signature of each function:

Syntax of fseek()

int fseek(FILE *stream, long offset, int whence);

It returns 0 when successful.

Syntax of rewind()

void rewind(FILE *stream);

As the rewind() function sets the file position indicator for the stream pointed to by the stream at the beginning of the file. It is also equivalent to

(void) fseek(stream, 0L, SEEK_SET);

except that the error indicator for the stream is also cleared, and it does not return any value making it harder to find whether the function was successful or not. This following code example sets the file pointer of an input stream back to the beginning using rewind(). But there is no way to check whether the rewind() was successful.

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

int main() {
    FILE* fptr = fopen("test.txt", "r");

    if (fp == NULL) {
        // Handle open error
    }

    // Do some processing with file

    // no way to check if rewind is successful
    rewind(fptr);

    // Do some more precessing with file
    return 0;
}

In the above code, fseek() can be used instead of rewind() to see if the operation succeeded.

The following lines of code can be used in place of rewind(fp);

if ( fseek(fp, 0L, SEEK_SET) != 0 ) {
	// Handle repositioning error
}