getgroups.2: ffix

[thirdparty/man-pages.git] / man2 / getgroups.2

diff --git a/man2/getgroups.2 b/man2/getgroups.2
index bd89eec2ce955205a0b39250f9d4bf08ddb757be..043e60677aa83adc978e2ee97c020a057a978ffa 100644 (file)
--- a/man2/getgroups.2
+++ b/man2/getgroups.2
@@ -29,7 +29,7 @@
 .\" 2008-05-03, mtk, expanded and rewrote parts of DESCRIPTION and RETURN
 .\"     VALUE, made style of page more consistent with man-pages style.
 .\"
-.TH GETGROUPS 2 2016-10-08 "Linux" "Linux Programmer's Manual"
+.TH GETGROUPS 2 2019-03-06 "Linux" "Linux Programmer's Manual"
 .SH NAME
 getgroups, setgroups \- get/set list of supplementary group IDs
 .SH SYNOPSIS
@@ -66,12 +66,13 @@ buffer pointed to by
 If the calling process is a member of more than
 .I size
 supplementary groups, then an error results.
+.PP
 It is unspecified whether the effective group ID of the calling process
 is included in the returned list.
 (Thus, an application should also call
 .BR getegid (2)
 and add or remove the resulting value.)
-
+.PP
 If
 .I size
 is zero,
@@ -93,6 +94,13 @@ The
 argument specifies the number of supplementary group IDs
 in the buffer pointed to by
 .IR list .
+A process can drop all of its supplementary groups with the call:
+.PP
+.in +4n
+.EX
+setgroups(0, NULL);
+.EE
+.in
 .SH RETURN VALUE
 On success,
 .BR getgroups ()
@@ -100,7 +108,7 @@ returns the number of supplementary group IDs.
 On error, \-1 is returned, and
 .I errno
 is set appropriately.
-
+.PP
 On success,
 .BR setgroups ()
 returns 0.
@@ -147,10 +155,11 @@ See the description of
 in
 .BR user_namespaces (7).
 .SH CONFORMING TO
+.BR getgroups ():
+SVr4, 4.3BSD, POSIX.1-2001, POSIX.1-2008.
+.PP
+.BR setgroups ():
 SVr4, 4.3BSD.
-The
-.BR getgroups ()
-function is in POSIX.1-2001 and POSIX.1-2008.
 Since
 .BR setgroups ()
 requires privilege, it is not covered by POSIX.1.
@@ -166,22 +175,24 @@ is defined in
 The set of supplementary group IDs
 is inherited from the parent process, and preserved across an
 .BR execve (2).
-
+.PP
 The maximum number of supplementary group IDs can be found at run time using
 .BR sysconf (3):
-.nf
-
-    long ngroups_max;
-    ngroups_max = sysconf(_SC_NGROUPS_MAX);
-
-.fi
+.PP
+.in +4n
+.EX
+long ngroups_max;
+ngroups_max = sysconf(_SC_NGROUPS_MAX);
+.EE
+.in
+.PP
 The maximum return value of
 .BR getgroups ()
 cannot be larger than one more than this value.
 Since Linux 2.6.4, the maximum number of supplementary group IDs is also
 exposed via the Linux-specific read-only file,
 .IR /proc/sys/kernel/ngroups_max .
-
+.PP
 The original Linux
 .BR getgroups ()
 system call supported only 16-bit group IDs.