linux多執行緒程式設計之互斥鎖
阿新 • • 發佈：2019-02-11
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
typedef struct pthread_mutex_related_tag
{
pthread_mutex_t mutex;
int lock_var;
time_t end_time;
}pthread_mutex_related;
static void mutex_init(pthread_mutex_related *pmr);
static void *test_func1();
static void *test_func2();
int main()
{
pthread_t pthread_id1 = 0;
pthread_t pthread_id2 = 0;
pthread_mutex_related *pmr = NULL;
pmr = (pthread_mutex_related *)malloc(sizeof(pthread_mutex_related));
mutex_init(pmr);
//1.pthread_1_create
if((pthread_create(&pthread_id1, NULL, test_func1, pmr))!=0){
perror("pthread_1_create./n");
}
//2.pthread_2_create
if((pthread_create(&pthread_id2, NULL, test_func2, pmr))!=0){
perror("pthread_2_create./n");
}
pthread_join(pthread_id1, NULL);
pthread_join(pthread_id2, NULL);
pthread_mutex_destroy(&pmr->mutex);
return 0;
}
static void mutex_init(pthread_mutex_related *pmr)
{
pmr->lock_var = 0;
pmr->end_time = time(NULL) + 1;
pthread_mutex_init(&pmr->mutex, NULL);
}
static void *test_func1(pthread_mutex_related *pmr)
{
while(time(NULL) < pmr->end_time){
//1.lock the mutex
if(pthread_mutex_lock(&pmr->mutex)!=0){
perror("[%s]pthread_mutex_lock");
}
else {
printf("pthread1 lock the buffer./n");
}
//2.can change var
pmr->lock_var ++;
//3.unlock the mutex
if(pthread_mutex_unlock(&pmr->mutex)!=0){
perror("[%s]pthread_mutex_unlock");
}
else {
printf("pthread1 unlock the buffer./n");
}
}
pthread_exit((void *)1);
}
static void *test_func2(pthread_mutex_related *pmr)
{
int ret = 0;
while (time(NULL) < pmr->end_time){
ret = pthread_mutex_trylock (&pmr->mutex);
if (ret == EBUSY){
printf("pthread2:the variable is locked by thread1./n");
}
else{
if (ret != 0){
perror ("[%s]pthread2_mutex_trylock");
}
else{
printf("pthread2: pthread2 lock the variable./n");
}
pmr->lock_var--;
ret = pthread_mutex_unlock (&pmr->mutex);
if (ret != 0){
perror ("[%s]pthread_mutex_lock");
}
sleep (3);
}
}
pthread_exit((void *)2);
}