getuid.2: Add NOTES explaining 32-bit system calls added in Linux 2.4

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man2/getuid.2 b/man2/getuid.2
index afa59d47ff1ffaceccb33117e416278bdf73c9b4..89975ed223bc54ef4fac5c10fe69c5a3808a2eb3 100644 (file)
--- a/man2/getuid.2
+++ b/man2/getuid.2
@@ -23,7 +23,7 @@
 .\" the source, must acknowledge the copyright and authors of this work.
 .\"
 .\" Historical remark, aeb, 2004-06-05
-.TH GETUID 2 1993-07-23 "Linux" "Linux Programmer's Manual"
+.TH GETUID 2 2010-11-22 "Linux" "Linux Programmer's Manual"
 .SH NAME
 getuid, geteuid \- get user identity
 .SH SYNOPSIS
@@ -54,6 +54,22 @@ UNIX V7 introduced separate calls
 .BR getuid ()
 and
 .BR geteuid ().
+.SH NOTES
+The original Linux
+.BR getuid ()
+and
+.BR geteuid ()
+system calls supported only 16-bit user IDs.
+Subsequently, Linux 2.4 added 
+.BR getuid32 ()
+and
+.BR geteuid32 (),
+supporting 32-bit IDs.
+The glibc
+.BR getuid ()
+and
+.BR geteuid ()
+wrapper functions transparently deal with the variations across kernel versions.
 .SH "SEE ALSO"
 .BR getresuid (2),
 .BR setreuid (2),