c/c++ linux 進程間通信系列7，使用pthread mutex
阿新 • • 發佈：2018-10-21
shm delete clu wait 進程間通信 pro -m printf gre
linux 進程間通信系列7，使用pthread mutex
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/shm.h> #include <pthread.h> #include <sys/wait.h> int main(){ pthread_mutex_t *m; pthread_mutexattr_t mat; int shmid; pid_t pid; shmid = shmget(IPC_PRIVATE, sizeof(pthread_mutex_t), 0600); if(shmid < 0){ perror("shmget"); return 1; } m = (pthread_mutex_t*)shmat(shmid, NULL, 0); //準備設定mutex的attribute pthread_mutexattr_init(&mat); //利用mutex進行進程間的通信 //底下這句沒有的話，這個mutex只在本進程間有作用 if(pthread_mutexattr_setpshared(&mat, PTHREAD_PROCESS_SHARED) != 0){ perror("pthread_mutexattr_setpshared"); return 1; } pthread_mutex_init(m, &mat); pid = fork(); printf("[%s] before pthread_mutex_lock()\n", pid == 0 ? "child" : "parent"); if(pthread_mutex_lock(m) != 0){ perror("pthread_mutex_lock"); return 1; } printf("[%s] press enter\n", pid == 0 ? "child" : "parent"); getchar(); if(pthread_mutex_unlock(m) != 0){ perror("pthread_mutex_unlock"); return 1; } printf("[%s] after pthread_mutex_lock()\n", pid == 0 ? "child" : "parent"); shmdt(m); if(pid != 0){ wait(NULL);//wait child process to complete printf("[%s] after wait()\n", pid == 0 ? "child" : "parent"); //delete shared memery if(shmctl(shmid, IPC_RMID, NULL) != 0){ perror("shmctl"); return 1; } } return 0; }
github源代碼
編譯方法：
g++ -g process-41-pthread-mutex.cpp -std=c++11 -pthread運行結果：
[parent] before pthread_mutex_lock()
[parent] press enter
[child] before pthread_mutex_lock()
敲回車
[parent] after pthread_mutex_lock()
[child] press enter
敲回車
[child] after pthread_mutex_lock()
[parent] after wait()
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c/c++ linux 進程間通信系列7，使用pthread mutex