#include <locale.h>
#include <stdio.h>
#include <time.h>
#include <string.h>

int
main(int argc, char *argv[])
{
	char date[256];
	time_t then = 1678658400;
	const char *locale = setlocale(LC_TIME, argv[1]);

	strftime(date, sizeof date, "%B", localtime(&then));
	printf("%s: %s (%u bytes)\n", locale, date, strlen(date));

	return 0;
}

##</code><code>##

use v5.10;
use POSIX qw(LC_ALL setlocale strftime);

my $locale = $ARGV[0];
say "$locale: ", POSIX::setlocale(LC_ALL, $locale);

my $march = strftime("%B", 0, 0, 0, 1, 2, 123);
say $march;