/*****
 *
 * Test program that evokes 'localtime'+threads bug
 *
 * Build:  gcc -o loctim_bug loctim_bug.c
 * Run:    ./loctim_bug.exe
 *
 *****/

#include <time.h>
#include <pthread.h>

#define MAX_THR  25
#define MAX_LOOP 10000

/* Set this to 24 minus your non-DST timezone */
/* For example, EDT = -5, therefore use 19    */
#define EXPECTED 19


void *
time_loop(void* data)
{
    int arg = *((int *)data);
    time_t when = (time_t)arg;
    int ii;
    struct tm *tm;
    struct timespec sleep, remainder;

    sleep.tv_sec = 0;
    sleep.tv_nsec = 1000;

    for (ii=0; ii < MAX_LOOP; ii++) {
        tm = localtime(&when);
        if (tm->tm_hour != EXPECTED)
            printf("BUG in thread %2d: expected: %d   got: %d\n",
                        arg, EXPECTED, tm->tm_hour);

        nanosleep(&sleep, &remainder);
    }
}


int
main(int argc, char **argv)
{
    int ii;
    pthread_t p_thread[MAX_THR];
    int args[MAX_THR+2];

    /* Launch threads */
    for (ii=0; ii < 50; ii++) {
        args[ii] = ii;
        pthread_create(&p_thread[ii], NULL, time_loop, (void*)&args[ii]);
    }

    /* Make sure threads finish */
    args[MAX_THR] = MAX_THR;
    time_loop((void*)&args[MAX_THR]);
    args[MAX_THR+1] = MAX_THR+1;
    time_loop((void*)&args[MAX_THR+1]);

    printf("Done\n");
}

/* EOF */