"Invalid Argument" error when globbing

Question

I've been trying to use the glob function in C to get a set of filenames in a directory where I store data. However I keep getting an error message that claims "Invalid Argument". I have no idea what argument it is refering to. Here is a sample code that produces the error

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <glob.h>

int main(int argc, char *argv[]){
    int j = 0, err = 0;
    glob_t *files = NULL;
    err = glob("*", GLOB_ERR | GLOB_MARK, NULL, files);
    if(err){
        printf("Error found: %s\n",strerror(errno));
        exit(err);
    }
    for(j = 0; j < files->gl_pathc; ++j){
        printf("%s\n",files->gl_pathv[j]);
    }
    return 0;
}

Looking foward for any suggestions

Answer 1

The way you are currently passing files there is no way glob() could actually populate it. Rather, what you want to do is:

glob_t files = { 0 };
err = glob("*", GLOB_ERR | GLOB_MARK, NULL, &files);

You should also call globfree(&files) later to clean up.