From 57d2facb7875b02b0b4d0bd1b5104ba14e1d378c Mon Sep 17 00:00:00 2001
From: Alejandro Colomar <alx.manpages@gmail.com>
Date: Mon, 10 May 2021 19:55:32 +0200
Subject: [PATCH] modify_ldt.2: Use syscall(SYS_...); for system calls without
 a wrapper

Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
---
 man2/modify_ldt.2 | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/man2/modify_ldt.2 b/man2/modify_ldt.2
index 8ce9ed252..b67a67690 100644
--- a/man2/modify_ldt.2
+++ b/man2/modify_ldt.2
@@ -27,11 +27,19 @@
 modify_ldt \- get or set a per-process LDT entry
 .SH SYNOPSIS
 .nf
-.BI "int modify_ldt(int " func ", void *" ptr ", unsigned long " bytecount );
+.BR "#include <asm/ldt.h>" "         /* Definition of " "struct user_desc" " */"
+.BR "#include <sys/syscall.h>" "     /* Definition of " SYS_* " constants */"
+.B #include <unistd.h>
+.PP
+.BI "int syscall(SYS_modify_ldt, int " func ", void *" ptr ,
+.BI "            unsigned long " bytecount );
 .fi
 .PP
 .IR Note :
-There is no glibc wrapper for this system call; see NOTES.
+glibc provides no wrapper for
+.BR modify_ldt (),
+necessitating the use of
+.BR syscall (2).
 .SH DESCRIPTION
 .BR modify_ldt ()
 reads or writes the local descriptor table (LDT) for a process.
@@ -168,9 +176,6 @@ is neither 0, 1, 2, nor 0x11.
 This call is Linux-specific and should not be used in programs intended
 to be portable.
 .SH NOTES
-Glibc does not provide a wrapper for this system call; call it using
-.BR syscall (2).
-.PP
 .BR modify_ldt ()
 should not be used for thread-local storage, as it slows down context
 switches and only supports a limited number of threads.