feof

Defined in header `<stdio.h>`
int feof( FILE *stream );

Checks if the end of the given file stream has been reached.

Parameters

stream

-

the file stream to check

Return value

nonzero value if the end of the stream has been reached, otherwise 0

Notes

This function only reports the stream state as reported by the most recent I/O operation, it does not examine the associated data source. For example, if the most recent I/O was a fgetc, which returned the last byte of a file, feof returns zero. The next fgetc fails and changes the stream state to end-of-file. Only then feof returns non-zero.

In typical usage, input stream processing stops on any error; feof and ferror are then used to distinguish between different error conditions.

Example

Run this code

#include <stdio.h>
#include <stdlib.h>
 
int main(void)
{
    int is_ok = EXIT_FAILURE;
    const char* fname = "/tmp/unique_name.txt"; // or tmpnam(NULL);
    FILE* fp = fopen(fname, "w+");
    if(!fp) {
        perror("File opening failed");
        return is_ok;
    }
    fputs("Hello, world!\n", fp);
    rewind(fp);
 
    int c; // note: int, not char, required to handle EOF
    while ((c = fgetc(fp)) != EOF) { // standard C I/O file reading loop
       putchar(c);
    }
 
    if (ferror(fp)) {
        puts("I/O error when reading");
    } else if (feof(fp)) {
        puts("End of file reached successfully");
        is_ok = EXIT_SUCCESS;
    }
 
    fclose(fp);
    remove(fname);
    return is_ok;
}

Possible output:

Hello, world!
End of file reached successfully

References

C11 standard (ISO/IEC 9899:2011):

7.21.10.2 The feof function (p: 339)

C99 standard (ISO/IEC 9899:1999):

7.19.10.2 The feof function (p: 305)

C89/C90 standard (ISO/IEC 9899:1990):

4.9.10.2 The feof function

Language
Headers
Type support
Program utilities
Variadic function support
Error handling
Dynamic memory management
Strings library
Algorithms
Numerics
Date and time utilities
Input/output support
Localization support
Concurrency support (C11)
Technical Specifications
Symbol index

clearerr	clears errors (function)
perror	displays a character string corresponding of the current error to stderr (function)
ferror	checks for a file error (function)