List the files in a Unix directory with C

This example C program demonstrates how to read the files in the current directory.

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>
#include <errno.h>

int main ()
{
    DIR * d;
    char * dir_name = ".";

    /* Open the current directory. */

    d = opendir (dir_name);

    if (! d) {
        fprintf (stderr, "Cannot open directory '%s': %s\n",
                 dir_name, strerror (errno));
        exit (EXIT_FAILURE);
    }
    while (1) {
        struct dirent * entry;
        
        entry = readdir (d);
        if (! entry) {
            break;
        }
        printf ("%s\n", entry->d_name);
    }
    /* Close the directory. */
    if (closedir (d)) {
        fprintf (stderr, "Could not close '%s': %s\n",
                 dir_name, strerror (errno));
        exit (EXIT_FAILURE);
    }

    return 0;
}

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The output of the example looks like this:

.
..
ld_c.html
tags
makefile
links-table
ld
ld.c
index.html
.gitignore
ld.txt