pthread

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>

void *thread_function(void *arg);

char message[] = "Hello world!\n";

int main() {
	int res;
	pthread_t a_thread;
	void *thread_result;

	res = pthread_create(&a_thread, NULL, thread_function, (void *)message);
	if(res != 0) {
		perror("Thread creation failed");
		exit(EXIT_FAILURE);
	}
	printf("Waiting for thread to finish...\n");
	res = pthread_join(a_thread, &thread_result);
	if(res != 0) {
		perror("Thread join failed");
		exit(EXIT_FAILURE);
	}
	printf("Thread joined, it returned %s\n", (char*)thread_result);
	printf("Message is now %s\n", message);
	exit(EXIT_SUCCESS);
}

void *thread_function(void *arg) {
	printf("Thread function is running, argument is %s\n", (char*)arg);
	sleep(3);
  strcpy(message, "Bye~");
	pthread_exit("Thank you for CPU time~");
}