54 struct pid {  struct
55 	SLIST_ENTRY(pid) next;
57 	pid_t pid;  argument
59 static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
68 	struct pid *cur;  in popen()
70 	int pdes[2], pid, twoway, cloexec;  in popen()  local
73 	struct pid *p;  in popen()
92 	if ((cur = malloc(sizeof(struct pid))) == NULL) {  in popen()
118 	switch (pid = vfork()) {  in popen()
169 	cur->pid = pid;  in popen()
193 	struct pid *cur, *last = NULL;  in pclose()
195 	pid_t pid;  in pclose()  local
219 		pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0);  in pclose()
220 	} while (pid == -1 && errno == EINTR);  in pclose()
224 	return (pid == -1 ? -1 : pstat);  in pclose()