C管道，fork，dup和exec（）

我正在尝试通过管道传递字符串列表到子进程，它应该通过/bin/cat使用execl() 。 我之前有工作，除了管道没有关闭所以程序一直在等待。 不知道我做了什么，现在根本不工作。 有人可以看到我的代码并告诉我，在子进程中cat没有显示str数据我做错了吗？

 int main(int argc, char** argv) { char *str[] = {"The", "quick", "brown", "fox", "jumped", "over", "the", "lazy", "dog"}; int fds[TOTAL_CHILDREN]; int writeFds; int catPID; int status; FILE * write_to_child; //create pipe if (pipe(fds) == -1) { perror("creating pipe: failed"); exit(EXIT_FAILURE); } pipe(fds); //create subprocess for cat child switch (catPID) { case 0: // successful creation of child close(fds[1]); //close write side from parents close(0); //close stdin dup(fds[0]); //connect pipe from execl cat to stdin execl("/bin/cat", "cat", (char *) 0); perror("exec failed!"); exit(20); break; case -1: //failure perror("fork failed: cat process"); exit(EXIT_FAILURE); default: //parent process close(fds[0]); writeFds = fds[1]; write_to_child = fdopen(fds[1], "w"); if (write_to_child == NULL) { perror("write to pipe failed"); exit(EXIT_FAILURE); } break; } int i; for (i = 0; i < 9; i++){ fprintf(write_to_child, "%s\n", str[i]); } fclose(write_to_child); close(writeFds); wait(&status); return (EXIT_SUCCESS); } 

Answer 1

您可能想要添加该行

 catPID = fork(); 

而且我不确定为什么你有两次pipe(fds)