getpgrp actually takes void. ask the IEEE...

include/unistd.h

@@ -80,7 +80,7 @@ uid_t	 geteuid __P((void));
 gid_t	 getgid __P((void));
 int	 getgroups __P((int, int *));		/* XXX (gid_t *) */
 char	*getlogin __P((void));
-pid_t	 getpgrp __P((int));
+pid_t	 getpgrp __P((void));
 pid_t	 getpid __P((void));
 pid_t	 getppid __P((void));
 uid_t	 getuid __P((void));

lib/libc/sys/getpgrp.2

@@ -38,14 +38,12 @@
 .Nm getpgrp
 .Nd get process group
 .Sh SYNOPSIS
+.Fd #include <unistd.h>
 .Ft pid_t
-.Fn getpgrp "int pid"
+.Fn getpgrp "void"
 .Sh DESCRIPTION
-The process group of the specified process is returned by
+The process group of the current process is returned by
 .Fn getpgrp .
-If
-.Fa pid
-is zero, the call applies to the current process.
 .Pp
 Process groups are used for distribution of signals, and
 by terminals to arbitrate requests for their input: processes
@@ -75,3 +73,16 @@ The
 .Nm
 function call appeared in
 .Bx 4.0 .
+.Sh STANDARDS
+The
+.Fn getpgrp
+function conforms to IEEE Std 1003.1-1988
+.Pq Dq Tn POSIX .
+.Sh COMPATABILITY
+This version of
+.Fn getpgrp
+differs from past Berkeley versions by not taking a
+.Fa "pid_t pid"
+argument.
+This incompatibility is required by
+.St -p1003.1-88 .

sys/kern/init_sysent.c

@@ -305,7 +305,7 @@ struct sysent sysent[] = {
 	3, mincore,			/* 78 = mincore */
 	2, getgroups,			/* 79 = getgroups */
 	2, setgroups,			/* 80 = setgroups */
-	1, getpgrp,			/* 81 = getpgrp */
+	0, getpgrp,			/* 81 = getpgrp */
 	2, setpgid,			/* 82 = setpgid */
 	3, setitimer,			/* 83 = setitimer */
 	compat(0,wait),		/* 84 = old wait */

sys/kern/syscalls.master

@@ -114,7 +114,7 @@
 78	STD	3 mincore
 79	STD	2 getgroups
 80	STD	2 setgroups
-81	STD	1 getpgrp
+81	STD	0 getpgrp
 82	STD	2 setpgid
 83	STD	3 setitimer
 84	COMPAT	0 wait