feat: 父子进程间，兄弟子进程间，使用管道 pipe 通信

Author: XMuli

11_pipe/childProcessPipe

@@ -0,0 +1,57 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+int main(int argc, char *argv[])
+{
+    int fd[2];   //用来标记管道的两端的文件描述符
+    int ret = pipe(fd);  //创建管道 pipe. fd[2] 是固定的输出参数
+
+    if (ret == -1) {
+        perror("[pipe create file] ");
+        return 0;
+    }
+        
+    int pipeRead = fd[0];   
+    int pipeWrite = fd[1];
+
+    int i = 0;
+    for ( ; i < 2; i++) {
+        pid_t pid = fork();
+        
+        if (pid == 0)
+            break;
+
+        if (pid == -1)
+            perror("[creator process file:]");
+
+    }
+
+    if (i == 0) {                         //child process 1
+        dup2(pipeWrite, STDOUT_FILENO);   
+        close(pipeRead);
+        execlp("ps", "ps", "aux", NULL);
+    } else if (i == 1) {                 //child process 2
+        dup2(pipeRead, STDIN_FILENO);    
+        close(pipeWrite);
+        execlp("grep", "grep", "bash", "--color=auto", NULL);
+    } else if (i == 2) {                 //parent process
+        close(pipeWrite);
+        close(pipeRead);
+
+        // sleep(2);
+        int wpid;
+        while ( wpid = waitpid(-1, NULL, WNOHANG) != -1) {  //回收子进程
+            if (wpid == 1) ///sbin/init splash 进程    /sbin/launchd
+                continue;
+
+            if (wpid == 0) 
+                continue;
+
+            printf("child dide pid = %d\n", wpid);
+        }    
+    }
+    
+    printf("pipeWrite = %d,  pipeRead = %d\n", pipeWrite, pipeRead);
+    return 0;
+}

11_pipe/childProcessPipe.cpp

@@ -26,10 +26,6 @@ int main(int argc, char *argv[])
         close(pipeWrite);
         execlp("grep", "grep", "bash", "--color=auto", NULL);
     }
-
-    close(pipeWrite);
-    close(pipeRead);
-
-    printf("pipeWrite = %d,  pipeRead = %d\n", pipeWrite, pipeRead);
+    
     return 0;
 }