我不明白如何在 sp.c 中使用pipe从 mp.cchild process创建的。我（我想我）在用于外部进程 file descriptor时似乎无法正确访问。execl
/***************mp.c*****************/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
int main(int argc, char *argv[]) {
char *procpath = "/mypath/sp";
char *procname = "sp";
pid_t pid;
int fd[2];
int ret;
char buf[20];
memset(&buf[0], 0, sizeof(buf));
ret = pipe(fd);
if(ret == -1){
perror("pipe");
exit(1);
}
pid = fork();
printf("%d\n",pid);
if (pid == 0){
//dup2(mypipefd[1],STDOUT_FILENO);
ret = execl(procpath, procpath, "1","2",NULL);
perror("execl failed to run slave program");
exit(1);
}
else if (pid > 0){
/* Parent process*/
printf("execl ret val = %d",ret);
printf("Parent process \n");
close(fd[1]);
read(fd[0],buf,15);
// close(fd[1]);
close(fd[0]);
printf("buf: %s TEST\n", buf);
printf("buf: %s TEST\n", buf);
}
else{
printf("call to fork failed, no child\n");
exit(-1);
}
exit(0);
}
和创建的过程...
/***************sp.c*****************/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
int main(int argc, char *argv[]){
int ret;
//printf("Child process \n");
int fd[2];
pipe(fd);
//dup2(fd[1],1);
//int out;
/*ret = dup2(fd[1],1);
if (ret = -1){
printf("%s\n", strerror(errno));
};*/
//sprintf()
//printf("%d\n", ret);
//mypipefd = argv[1];
printf("Child process \n");
//close(fd[0]);
write(fd[1], "Hello there!",12);
close(fd[1]);
exit(0);
}