C 如何使子线程等待主线程

我有两个线程：一个子线程检测鼠标事件，另一个主线程执行程序

全局变量：

子线程：

主线程：

我的问题是：当我的主线程正在等待时，我的子线程正在使用100%1核心处理器，那么我可以使用哪个函数将子线程与主线程暂停

---

我已经咨询过了，但它并没有完全帮助我。

所以，如果您想暂停主线程，直到子线程发出关于它结束的信号，您可以使用互斥锁来锁定主线程：

#include "stdio.h"
#include "pthread.h"

/* I work on windows now, so i need windows sleep function to test example */
/* platform independed sleep function */
#ifdef _WIN32
# include "windows.h"
# define platform_sleep(ms) Sleep(ms)
#else
# include "unistd.h"
# define platform_sleep(s) sleep(s / 1000)
#endif


pthread_mutex_t mtx;


void *
child_func(void *arg)
{
    /* simulate some hard work */
    platform_sleep(3000); /* 3 secs */

    /* after this "hard work" we allow main thread to continue */
    pthread_mutex_unlock(&mtx);
}



int
main()
{
    pthread_mutex_init(&mtx, NULL);
    pthread_mutex_lock(&mtx);

    pthread_t child;
    pthread_create(&child, NULL, child_func, NULL);

    /* mutex is already locked by main thread, so it waits */
    /* until child thread unlock it */
    pthread_mutex_lock(&mtx);
    pthread_mutex_destroy(&mtx);

    /* do work after child ends */
}

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您可以使用a来减轻cpu的负载。@Sanderedycker您使用多少时间来减轻cpu的负载？我用500毫秒进行测试，我的cpu总是在25%使用（使用四核）@sanderedycker我在我的程序中添加了follinwing行：

if（g_wait）{struct timespec waiting；waiting.tv_sec=0；waiting.tv_nsec=500000；nanosleep（&waiting，NULL）}

您可以使用，我认为g_wait应该是一个原子，“等待主程序”是什么意思？在允许子线程停止等待之前，您希望主线程做什么？在我的子线程中有一个

while

功能，因此我不确定我是否能够像那样使用

pthread\u mutex\u unlock

，是我的用户决定暂停并恢复程序，不是定义等待时间的任意值time@damadam，pause只是一个例子，当然你可以使用循环和其他东西。

void *mouseEvent2(void *arg) 
{
int fd;
struct input_event ev;
const char* pFile = "/dev/input/event0";

signal(SIGINT, SAMPLE_VGS_HandleSig);
signal(SIGTERM, SAMPLE_VGS_HandleSig);

fd = open(pFile, O_RDONLY);
if (fd == -1) {
    printf("ERROR Opening %s\n", pFile);
    return NULL;
}

while(scroll != -1) {
    read(fd, &ev, sizeof(ev));

    [... Some code with if statement ... ]
    if(...) //left mouse button
        g_wait = !g_wait;

    [need waiting so the thread won't use at 100% a core]
}
close(fd);
(void) arg;
pthread_exit(NULL);
}

int main() {
[... some code and initilisation here ...]
if(pthread_create(&scrollThread, NULL, mouseEvent2, NULL))
    goto _FAILURE_;
do {
    [...]
    while(g_wait);
}
[... some deinit ...]
_FAILURE_ :
pthread_join(scrollThread, NULL);
[... some other deinit ...]
return 0;
}

#include "stdio.h"
#include "pthread.h"

/* I work on windows now, so i need windows sleep function to test example */
/* platform independed sleep function */
#ifdef _WIN32
# include "windows.h"
# define platform_sleep(ms) Sleep(ms)
#else
# include "unistd.h"
# define platform_sleep(s) sleep(s / 1000)
#endif


pthread_mutex_t mtx;


void *
child_func(void *arg)
{
    /* simulate some hard work */
    platform_sleep(3000); /* 3 secs */

    /* after this "hard work" we allow main thread to continue */
    pthread_mutex_unlock(&mtx);
}



int
main()
{
    pthread_mutex_init(&mtx, NULL);
    pthread_mutex_lock(&mtx);

    pthread_t child;
    pthread_create(&child, NULL, child_func, NULL);

    /* mutex is already locked by main thread, so it waits */
    /* until child thread unlock it */
    pthread_mutex_lock(&mtx);
    pthread_mutex_destroy(&mtx);

    /* do work after child ends */
}