这个问题在这里已经有了答案:
pthread_mutex_lock returns invalid argument
(2 个回答)
6年前关闭。
我正在学习如何在 C 中使用 Pthread。我尝试使用 pthread_mutex_lock
.锁定成功时应该返回0。但是我的程序总是返回 22 - 无效的参数。
代码如下:
pthread_mutex_lock
is used inwork_function
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#define N 2
void *work_function(void *param);
int count=0;
pthread_mutex_t mut;
int main(int args, char **argv)
{
pthread_t tid[N];
long int iterations = atoi(argv[1]);
pthread_create(&tid[0], NULL, work_function, (void *) iterations);
pthread_create(&tid[1], NULL, work_function, (void *) iterations);
pthread_join(tid[1], NULL);
pthread_join(tid[0], NULL);
if (count != iterations * 2)
printf("Error: %d\n",count);
else
printf("Value as expected: count = %d\n", count);
pthread_exit(NULL);
}
void *work_function(void *param)
{
long int max_iter = (long int) param;
int i, tmp;
pid_t pid = getpid();
pthread_t id = pthread_self();
i = pthread_mutex_lock(&mut);
printf("%d\n", i);
for(i = 0; i < max_iter; i++) {
tmp = count;
tmp ++;
printf("in thread: pid=%d and id=%u count=%d new\n", (unsigned int) pid, (unsigned int) id, count);
// sleep(1);
count = tmp;
printf("haha\n");
}
pthread_mutex_unlock(&mut);
pthread_exit(NULL);
}
当
3
时产生以下结果作为命令行参数传入。22
22
in thread: pid=36767 and id=6819840 count=0 new
in thread: pid=36767 and id=7356416 count=0 new
haha
haha
in thread: pid=36767 and id=6819840 count=1 new
in thread: pid=36767 and id=7356416 count=1 new
haha
haha
in thread: pid=36767 and id=6819840 count=2 new
in thread: pid=36767 and id=7356416 count=2 new
haha
haha
Error: 3
最佳答案
正在初始化 pthread_mutex_t mut
通过将以下代码放在 main
下解决了我的问题方法。
pthread_mutex_init(&mut, NULL);
关于c - pthread_mutex_lock 在 C 中返回 22,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30511046/