relibc/tests/time/localtime.c

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

#include "test_helpers.h"

int main(void) {
    int day = 60 * 60 * 24;
    time_t inputs[] = { -(day * 33), -day, -1, -500, 0, 1, 1531454950 };
    for (int i = 0; i < (sizeof(inputs) / sizeof(time_t)); i += 1) {
        struct tm* t = localtime(&inputs[i]);

        printf(
            "Year %d, Day of year: %d, Month %d, Day of month: %d, Day of week: %d, %d:%d:%d\n",
            t->tm_year, t->tm_yday, t->tm_mon, t->tm_mday, t->tm_wday, t->tm_hour, t->tm_min, t->tm_sec
        );
    }

    time_t input = 1531461823;
    fputs(ctime(&input), stdout); // Omit newline

    char ctime_r_buffer[26];
    /* ctime_r() generally returns the address of the provided buffer,
     * but may return NULL upon error according to the spec. */
    char *ctime_r_result = ctime_r(&input, ctime_r_buffer);
    if (ctime_r_result == ctime_r_buffer) {
        fputs(ctime_r_result, stdout);
    }
    else {
        printf("Unexpected pointer from ctime_r: %p\n", ctime_r_result);
    }
}