Thread: Advice requested, Code makes sense to me, not compiler

Even though you're using different names (current, ip, whatever) the pointers are all pointing at the same file structure; so if you want to re-read the file from the beginning you'll have to rewind the file pointer.

(And if it makes you feel better, it compiles on my system, but with some unused variable warnings and a comparison between signed and unsigned in getword_max.)

Made all changes noted above, and its still not decending into the while loop, so the pointers must be screwing up somewhere, but i dont understand why.

Each time i create a new pointer, assign it to the original file pointer, so as far as i understand it, thats two separate pointers pointing to the same original file location.

Then i take the copy, and mess around with it, so the original should still be the same?

Originally Posted by andrew.bolster

Made all changes noted above, and its still not decending into the while loop, so the pointers must be screwing up somewhere, but i dont understand why.

Each time i create a new pointer, assign it to the original file pointer, so as far as i understand it, thats two separate pointers pointing to the same original file location.

Then i take the copy, and mess around with it, so the original should still be the same?

Compare the following code:

Code:

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

void readfile(FILE *fileptr) {
    FILE *ip;
    char nextfive[6];
    ip = fileptr;
    fgets(nextfive, 6, ip);
    printf("%s\n", nextfive);
}

int main(void) {
    FILE *infile;
    infile = fopen("test.txt", "r");
    readfile(infile);
    readfile(infile);
    readfile(infile);
    fclose(infile);
    return 0;
}

(Note the copying of file pointers inside the function.) Tell me what you think it does, then run it and see what it does.