parent_fd          47 popen.cpp        int parent_fd, child_fd;
parent_fd          88 popen.cpp            parent_fd = pipe_fds[0];
parent_fd          92 popen.cpp            parent_fd = pipe_fds[1];
parent_fd         102 popen.cpp          close(parent_fd);
parent_fd         128 popen.cpp          close(parent_fd);
parent_fd         134 popen.cpp          fp = fdopen(parent_fd, new_mode);
parent_fd         136 popen.cpp            fcntl(parent_fd, F_SETFD, 0);