qfedu-linux-advanced-level/day7/nomutex_3.c

54 lines
1.4 KiB
C

#include <stdio.h>
#include <pthread.h>
#include <unistd.h>
// 静态初始化互斥锁
// pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
// 动态初始化锁-定义锁
pthread_mutex_t mutex;
void *printer(void *data)
{
char *msg = (char *)data;
int lock_acquired = 0; // 未获取到锁
while (!lock_acquired) // 未获取到锁的时候,循环尝试获取锁,并处理
{
// trylock 非阻塞锁
if (pthread_mutex_trylock(&mutex) == 0) // 如果拿到锁
{
lock_acquired = 1; // 该状态:已获取到锁
while (*msg) // 当前线程传入的字符串未读取完成时,循环读取
{
printf("%c", *msg++);
fflush(stdout);
usleep(200 * 1000);
}
pthread_mutex_unlock(&mutex); // 读完后,解锁当前进程
}
else
{
usleep(100); // 0.1 毫秒后继续尝试获取锁
}
}
return NULL;
}
int main(int argc, char const **argv)
{
// 动态初始化锁-初始化
pthread_mutex_init(&mutex, NULL);
pthread_t tid1, tid2;
pthread_create(&tid1, NULL, printer, "disen666\n");
pthread_create(&tid2, NULL, printer, "lucy888\n");
pthread_join(tid1, NULL);
pthread_join(tid2, NULL);
printf("\n---over---\n");
// 销毁互斥锁
pthread_mutex_destroy(&mutex);
return 0;
}