From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 17 May 2023 18:50:27 +0000 (-0700)
Subject: Improve AC_FUNC_MMAP comments
X-Git-Tag: v2.72d~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8e7281d7bebb5e389befe6e9a5afbb7b2ae13ae0;p=thirdparty%2Fautoconf.git

Improve AC_FUNC_MMAP comments

* lib/autoconf/functions.m4 (AC_FUNC_MMAP): Add comment.
---

diff --git a/lib/autoconf/functions.m4 b/lib/autoconf/functions.m4
index 3d6e4aca..54d04cc3 100644
--- a/lib/autoconf/functions.m4
+++ b/lib/autoconf/functions.m4
@@ -1311,6 +1311,8 @@ AC_CACHE_CHECK([for working mmap], [ac_cv_func_mmap_fixed_mapped],
 #include <sys/mman.h>
 
 #ifndef getpagesize
+/* Prefer sysconf to the legacy getpagesize function, as getpagesize has
+   been removed from POSIX and is limited to page sizes that fit in 'int'.  */
 # ifdef _SC_PAGESIZE
 #  define getpagesize() sysconf (_SC_PAGESIZE)
 # elif defined _SC_PAGE_SIZE