问题：
[单选题]下面的程序是为了实现“ls /dev|grep sd”。请选择合适的语句将其补充完整。 #include #include #include main(){ int pipefd[2]; int rv; pipe(pipefd); rv=fork(); if(0==rv){ ________; close(0); dup(pipefd[0]); close(pipefd[0]); execlp("grep", "grep", "sd", NULL); }else{ ________; close(1); dup(pipefd[1]); close(pipefd[1]); execlp("ls", "ls", "/dev", NULL); } }
Aclose(pipefd[1]) close(pipefd[0])
Bclose(pipefd[0]) close(pipefd[1])
Cclose(pipefd[0]) close(pipefd[0])
Dclose(pipefd[1]) close(pipefd[1])
