restructure

TMP/Practice/trash/child.c

@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#define DATA 20
+#define NUM 4
+
+struct Data {
+    char s[DATA + 1];
+    pid_t cpid;
+    unsigned char i, t;
+};
+
+int main(int argc, char *argv[]){
+    int pipefd[4][2];
+    pid_t cpid[4];
+    unsigned char i, tt;
+    int rr, wt;
+
+if (argc != 2){
+    fprintf(stderr, "Usage: %s <string>\n", argv[0]);
+    exit(EXIT_FAILURE);
+}
+
+srand(time(NULL));
+
+for(i = 0; i < NUM; i++){
+    if (pipe(pipefd[i]) == -1){
+        perror("Pipe");
+        exit(EXIT_FAILURE);
+    }
+    tt = (unsigned char)rand()%8;
+    dprintf(STDOUT_FILENO, "Time[%X]\n", tt);
+
+    cpid[i] = fork();
+    if (cpid[i] == -1){
+        perror("Fork");
+        exit(EXIT_FAILURE);
+    }
+
+    if (cpid[i] == 0){
+        struct Data data;
+        close(pipefd[i][0]);
+        for(int j = 0; j < i; j++){
+            close(pipefd[j][0]);
+            close(pipefd[j][1]);
+        }
+        data.cpid = getpid();
+        data.i = i;
+        data.t = tt;
+        strncpy(data.s, argv[1], DATA);
+        write(pipefd[i][1], &data, sizeof(struct Data));
+        close(pipefd[i][1]);
+        sleep(tt);
+        _exit(EXIT_FAILURE);
+    } else {
+        dprintf(STDOUT_FILENO, "Start [%d]\n", cpid[i]);
+        close(pipefd[i][1]);
+    }
+}
+
+printf("Waiting...\n");
+
+while((wt = waitpid(-1, NULL, WNOHANG)) > -1){
+    if (wt > 0) for(i = 0; i < NUM; i++){
+        if (cpid[i] == wt){
+            struct Data data;
+            while((rr = read(pipefd[i][0], &data, sizeof(struct Data))) > 0){
+                dprintf(STDOUT_FILENO, "[%d] num = %d, time = %d [%s]\n", data.cpid, data.i, data.t, data.s);
+            }
+            if (rr == 0) close(pipefd[i][0]);
+        }
+    }
+    usleep(3000000);
+}
+if (errno == ECHILD)
+    perror("Finish:");
+else
+    perror("Wait error:");
+    exit(EXIT_SUCCESS);
+}