SymbX/systemd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

include: fix limits.h override

Browse Source 
This is especially necessary since GCC 16.x.

=====
$ gcc --version
gcc (GCC) 16.2.1 20260819 (Red Hat 16.2.1-2)
Copyright (C) 2026 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
=====

Without this change, /usr/include/limits.h is not included, hence POSIX
constants are not defined:
=====
$ echo '#include <limits.h>' | gcc -E -H -isystem ~/git/systemd/src/include/musl - 2>&1 >/dev/null | grep '^\..*limit'
. /home/watanabe/git/systemd/src/include/musl/limits.h
.. /usr/lib/gcc/x86_64-redhat-linux/16/include/limits.h
... /usr/lib/gcc/x86_64-redhat-linux/16/include/syslimits.h
=====

With this change, /usr/include/limits.h is included, thus POSIX
constants are defined:
=====
$ echo '#include <limits.h>' | gcc -E -H -isystem ~/git/systemd/src/include/musl - 2>&1 >/dev/null | grep '^\..*limit'
. /home/watanabe/git/systemd/src/include/musl/limits.h
.. /usr/lib/gcc/x86_64-redhat-linux/16/include/limits.h
... /usr/include/limits.h
...... /usr/include/linux/limits.h
.. /usr/lib/gcc/x86_64-redhat-linux/16/include/limits.h
=====

Replaces #43824.
This commit is contained in:
Yu Watanabe
2026-09-22 18:14:12 +09:00
parent e362a4efcb
commit 6a131b32e0
1 changed files with 20 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/include/musl/limits.h
+20
View File
@@ -1,6 +1,26 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
/* GCC introduces a spurious, tricky inclusion cycle:
* GCC's limits.h
* -> GCC's syslimits.h
* -> GCC's limits.h (again!!!)
* -> glibc/musl's limits.h
* -> define POSIX defines
* -> define ISO C defines
* This works only when GCC's limits.h is included first, but a user override breaks the cycle. Hence, we
* need to manually achieve the cycle here. If GCC is not used (e.g., Clang), then including the compiler's
* limits.h twice should be redundant but harmless. */
/* First, get the POSIX defines from glibc/musl's limits.h. When the two macros below are defined, GCC's
* limits.h includes the next limits.h, that is, one from glibc/musl. */
#define _GCC_LIMITS_H_
#define _GCC_NEXT_LIMITS_H
#include_next <limits.h> /* IWYU pragma: export */
#undef _GCC_NEXT_LIMITS_H
#undef _GCC_LIMITS_H_
/* Next, get the ISO C defines from GCC's limits.h. */
#include_next <limits.h> /* IWYU pragma: export */
#include <assert.h>