Quick start

This example calculates the prayer times for Jakarta on 12 July 2026 using the KEMENAG (Indonesia) method and prints each time as HH:MM.

The program

example.c

#define PRAYERTIMES_IMPLEMENTATION
#include "prayertimes.h"
#include <stdio.h>

int main(void) {
    // 1. Pick a calculation method from the built-in catalogue.
    const MethodParams *params = method_params_get(CALC_KEMENAG);

    // 2. Compute the times for a date, location and UTC offset.
    struct PrayerTimes t = calculate_prayer_times(
        2026, 7, 12,        // year, month, day
        -6.2088, 106.8456,  // latitude, longitude (Jakarta)
        7.0,                // UTC+7 (numeric offset in hours)
        params);

    // 3. Format the results. Times come back as decimal hours.
    char buf[16];
    format_time_hm(t.fajr, buf, sizeof buf);    printf("Fajr     %s\n", buf);
    format_time_hm(t.dhuhr, buf, sizeof buf);   printf("Dhuhr    %s\n", buf);
    format_time_hm(t.asr, buf, sizeof buf);     printf("Asr      %s\n", buf);
    format_time_hm(t.maghrib, buf, sizeof buf); printf("Maghrib  %s\n", buf);
    format_time_hm(t.isha, buf, sizeof buf);    printf("Isha     %s\n", buf);
    return 0;
}

Build and run

cc example.c -lm -o example
./example

Output

Fajr     04:44
Dhuhr    12:01
Asr      15:23
Maghrib  17:54
Isha     19:09

note

Times depend on the calculation method, the location and the offset. Change any of them and the output changes.

Letting the library resolve the time zone

In the example above the UTC offset (7.0) is hard-coded. If you would rather have the offset resolved from an IANA time zone, with daylight saving handled automatically, include the optional timezone.h helper.

caution

timezone.h must be included before any system header in that translation unit, because it sets a feature-test macro that glibc reads the first time <features.h> is pulled in. <time.h> is the obvious one, but prayertimes.h includes <math.h>, which is enough to lock the setting in. Put timezone.h first and the order can never be wrong.

Getting this wrong is silent under the default gnu11 dialect and a compile error under -std=c11.

example_tz.c

#define MUSLIM_TIMEZONE_IMPLEMENTATION
#include "timezone.h"   // must come before any system header

#define PRAYERTIMES_IMPLEMENTATION
#include "prayertimes.h"

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

int main(void) {
    time_t when = time(NULL);
    double offset;
    if (parse_timezone_offset("Asia/Jakarta", when, &offset) != 0) {
        fprintf(stderr, "cannot resolve time zone\n");
        return 1;
    }

    const MethodParams *params = method_params_get(CALC_KEMENAG);
    struct PrayerTimes t = calculate_prayer_times(
        2026, 7, 12, -6.2088, 106.8456, offset, params);

    char buf[16];
    format_time_hm(t.dhuhr, buf, sizeof buf);
    printf("Dhuhr %s\n", buf);
    return 0;
}

See the API reference for the full list of types and functions.