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39 | /*
* Copyright 2021 Jeisson Hidalgo-Cespedes - Universidad de Costa Rica
* Creates a secondary thread that greets in the standard output
*/
#include <pthread.h>
#include <stdio.h>
void* run(void* data) {
pthread_mutex_t* stdout_mutex = (pthread_mutex_t*)data;
pthread_mutex_lock(stdout_mutex);
printf("Hello from secondary thread, mutex at %p\n", data);
pthread_mutex_unlock(stdout_mutex);
return NULL;
}
int main(void) {
pthread_t thread;
pthread_mutex_t stdout_mutex;
int error = pthread_mutex_init(&stdout_mutex, /*attr*/ NULL);
if (error == 0) {
error = pthread_create(&thread, NULL, run, &stdout_mutex);
if (error == 0) {
pthread_mutex_lock(&stdout_mutex);
printf("Hello from main thread\n");
pthread_mutex_unlock(&stdout_mutex);
pthread_join(thread, NULL);
} else {
fprintf(stderr, "error: could not create a secondary thread\n");
}
pthread_mutex_destroy(&stdout_mutex);
} else {
fprintf(stderr, "error: could not init mutex\n");
}
return 0;
}
// lock == mutex: mutual exclusion
|