perl -e '$s = rename("tags", "tags"); print STDOUT ($s ? "OK" : "FAIL"), "\n";'

##</code><code>##

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

int
main (int argc, char **argv)
{
    int rs;

    rs = rename(argv[1], argv[1]);

    if (-1 == rs) {
        fprintf(stderr, "Error renaming %s: %s\n", argv[1], strerror(errno));
    } else {
        printf("Rename of %s is OK\n", argv[1]);
    }

    exit(0);
}