问为什么“while（！feof（file））”总是错的？

#include <stdio.h>

#include <stdlib.h>

int main(int argc, char **argv)

{

    char * path = argc > 1 ? argv[1] : "input.txt";

    FILE * fp = fopen(path, "r");

    if( fp == NULL ) {

        perror(path);

        return EXIT_FAILURE;

    }

    while( !feof(fp) ) {  /* THIS IS WRONG */

        /* Read and process data from file… */

    }

    fclose(fp);

    return EXIT_SUCCESS;

}