On 5/9/23 18:40, Sam James wrote:
It looks like this is still the case in master as well.
Thanks for reporting that. Simply including unistd.h isn't enough in
general, as POSIX no longer requires getpagesize to be declared there.
So I instead installed the attached patch, which changes the test so
that it doesn't use getpagesize. This is a conservative-enough approach
that it should be OK to squeeze it in before the next Autoconf release.From 028526149ee804617a302ccef22cc6adbda681b0 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Wed, 10 May 2023 17:20:49 -0700
Subject: [PATCH] Port AC_FUNC_MMAP to more-modern systems
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
* lib/autoconf/functions.m4 (AC_FUNC_MMAP): Don’t call
getpagesize, as it’s tricky to configure, modern POSIX doesn’t
require it, and calling it without including <unistd.h> provokes a
compile-time error on modern systems. Instead, rework the test
to not need getpagesize. Add a FIXME comment for unnecessary
tests; I don't want to remove them now as we're too close to
a release. Remove long-obsolete comment about GNU grep.
---
lib/autoconf/functions.m4 | 44 +++++----------------------------------
1 file changed, 5 insertions(+), 39 deletions(-)
diff --git a/lib/autoconf/functions.m4 b/lib/autoconf/functions.m4
index 499e4c02..5a0f0185 100644
--- a/lib/autoconf/functions.m4
+++ b/lib/autoconf/functions.m4
@@ -1283,6 +1283,7 @@ AU_ALIAS([AM_FUNC_MKTIME], [AC_FUNC_MKTIME])
AN_FUNCTION([mmap], [AC_FUNC_MMAP])
AC_DEFUN([AC_FUNC_MMAP],
[AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+dnl FIXME: Remove the unnecessary checks for unistd.h, sys/param.h, getpagesize.
AC_CHECK_HEADERS_ONCE([unistd.h sys/param.h])
AC_CHECK_FUNCS_ONCE([getpagesize])
AC_CACHE_CHECK([for working mmap], [ac_cv_func_mmap_fixed_mapped],
@@ -1305,48 +1306,11 @@ AC_CACHE_CHECK([for working mmap], [ac_cv_func_mmap_fixed_mapped],
VM page cache was not coherent with the file system buffer cache
like early versions of FreeBSD and possibly contemporary NetBSD.)
For shared mappings, we should conversely verify that changes get
- propagated back to all the places they're supposed to be.
-
- Grep wants private fixed already mapped.
- The main things grep needs to know about mmap are:
- * does it exist and is it safe to write into the mmap'd area
- * how to use it (BSD variants) */
+ propagated back to all the places they're supposed to be. */
#include <fcntl.h>
#include <sys/mman.h>
-/* This mess was copied from the GNU getpagesize.h. */
-#ifndef HAVE_GETPAGESIZE
-# ifdef _SC_PAGESIZE
-# define getpagesize() sysconf(_SC_PAGESIZE)
-# else /* no _SC_PAGESIZE */
-# ifdef HAVE_SYS_PARAM_H
-# include <sys/param.h>
-# ifdef EXEC_PAGESIZE
-# define getpagesize() EXEC_PAGESIZE
-# else /* no EXEC_PAGESIZE */
-# ifdef NBPG
-# define getpagesize() NBPG * CLSIZE
-# ifndef CLSIZE
-# define CLSIZE 1
-# endif /* no CLSIZE */
-# else /* no NBPG */
-# ifdef NBPC
-# define getpagesize() NBPC
-# else /* no NBPC */
-# ifdef PAGESIZE
-# define getpagesize() PAGESIZE
-# endif /* PAGESIZE */
-# endif /* no NBPC */
-# endif /* no NBPG */
-# endif /* no EXEC_PAGESIZE */
-# else /* no HAVE_SYS_PARAM_H */
-# define getpagesize() 8192 /* punt totally */
-# endif /* no HAVE_SYS_PARAM_H */
-# endif /* no _SC_PAGESIZE */
-
-#endif /* no HAVE_GETPAGESIZE */
-
int
main (void)
{
@@ -1355,7 +1319,9 @@ main (void)
int i, pagesize;
int fd, fd2;
- pagesize = getpagesize ();
+ /* The "page size" need not equal the system page size,
+ and need not even be a power of 2. */
+ pagesize = 8192;
/* First, make a file with some known garbage in it. */
data = (char *) malloc (pagesize);
--
2.40.1
