首先是execl执行的程序 pipe.c

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string.h>

int main(int argc, char* argv[]){
        int fd[2];
        int pid;
        char words[]="This is ABCDEFGHIJKLMNOPRSRUWXYZ";
        char buff[50];
        if(pipe(fd)<0){
                printf("bad pipe");
                exit(1);
        }
        pid = fork();
        if(pid<0){
                printf("fork failed");
        }
        else if(pid > 0){
                close(fd[0]);
                write(fd[1],words,strlen(words)+1);
                write(fd[1],"??????????",11);
                //printf("parent writing finished\n");
        }
        else{
                close(fd[1]);
                read(fd[0],buff, strlen(words)+1);
                printf("child read content: %s\n", buff);
                read(fd[0],buff, strlen(words)+1);
                printf("child read content: %s\n", buff);
        }
        exit(0);
}

调用 execl的程序 iterate.c

#include <sys/stat.h>
#include <fcntl.h>

int main(int argc, char* argv[]){

        int pid,times, fd, ret;
        char val[20];
        times = atoi(argv[2]);
        //fd = open("./stdio",O_WRONLY|O_CREAT);
        //write(fd,"111",4);
        //close(fd);
        while(times--){
                pid = fork();
                if(pid < 0){
                        printf("fork failed\n");
                        exit(-1);
                }
                else if(pid == 0){
                                  printf("[%d]", times); //这个printf不输出任何信息
                                                execl(argv[1],NULL);   //
                }
        }
}

iterate.c 里面的printf不输出东西，调试发现返回值是正确的。 论坛里的朋友们，可以指教一下么？

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