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#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
typedef struct {
long ninc_per_thread;
long a;
long b;
long r;
long * p;
pthread_mutex_t * m;
} arg_t;
void * f(void * arg_) {
arg_t * arg = (arg_t *)arg_;
long a = arg->a, b = arg->b;
long ninc_per_thread = arg->ninc_per_thread;
if (b - a == 1) {
int i;
for (i = 0; i < ninc_per_thread; i++) {
pthread_mutex_lock(arg->m);
arg->p[0]++;
pthread_mutex_unlock(arg->m);
}
arg->r = a;
} else {
long c = (a + b) / 2;
arg_t cargs[2] = { { ninc_per_thread, a, c, 0, arg->p, arg->m },
{ ninc_per_thread, c, b, 0, arg->p, arg->m } };
pthread_t tid;
pthread_create(&tid, 0, f, cargs);
f(cargs + 1);
pthread_join(tid, 0);
arg->r = cargs[0].r + cargs[1].r;
}
return 0;
}
pthread_mutex_t m[1] = { PTHREAD_MUTEX_INITIALIZER };
int main(int argc, char ** argv) {
long nthreads = (argc > 1 ? atol(argv[1]) : 100);
long ninc_per_thread = (argc > 2 ? atol(argv[2]) : 10000);
long p[1] = { 0 };
arg_t arg[1] = { { ninc_per_thread, 0, nthreads, 0, p, m } };
pthread_t tid;
pthread_create(&tid, 0, f, arg);
pthread_join(tid, 0);
if (arg->r == (nthreads - 1) * nthreads / 2
&& arg->p[0] == nthreads * ninc_per_thread) {
printf("OK\n");
return 0;
} else {
printf("NG: p = %ld != nthreads * ninc_per_thread = %ld\n",
arg->p[0], nthreads * ninc_per_thread);
return 1;
}
}
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