diff mbox series

libstdc++: Fix up FAIL in 17_intro/names.cc on glibc < 2.19 [PR108568]

Message ID Y9OZibQSy8DYxwbd@tucnak
State Unresolved
Headers
Series libstdc++: Fix up FAIL in 17_intro/names.cc on glibc < 2.19 [PR108568] |

Checks

Context Check Description
snail/gcc-patch-check warning Git am fail log

Commit Message

Jakub Jelinek Jan. 27, 2023, 9:29 a.m. UTC 
  Hi!

On gcc112 which has glibc 2.17 I've noticed
FAIL: 17_intro/names.cc (test for excess errors)
FAIL: experimental/names.cc (test for excess errors)
These are because glibc < 2.19 used __unused as field member of various structs,
including mcontext_t in sys/ucontext.h on ppc64le.
This was changed in glibc with
https://gcc.gnu.org/pipermail/libc-alpha/2013-November/045766.html
names.cc even has
#ifdef __GLIBC_PREREQ
#if ! __GLIBC_PREREQ(2, 19)
// Glibc defines this prior to 2.19
#undef __unused
#endif
#endif
for it, but it doesn't work.  The reason is that __GLIBC_PREREQ is defined in
<features.h> but nothing included that header before this spot (it is included later
from bits/stdc++.h).

The following patch on Linux/Hurd conditionally includes features.h to get
the needed macros before deciding if __unused should be undefined or not.
If needed, I could use __GLIBC_PREREQ then but would need to check if it is
defined and between 1996 and 1999 it wasn't.

Tested on powerpc64le-linux with glibc 2.17 (where it fixes the
regressions), on x86_64-linux with glibc 2.35 (where it still PASSes),
plus on the latter with -E -dD on the test to verify __unused is just
defined and not undefined later on, ok for trunk?

2023-01-27  Jakub Jelinek  <jakub@redhat.com>

	PR libstdc++/108568
	* testsuite/17_intro/names.cc (__unused): For linux or GNU hurd
	include features.h if present and then check __GLIBC__ and
	__GLIBC_MINOR__ macros for glibc prior to 2.19, instead of testing
	__GLIBC_PREREQ which isn't defined yet.


	Jakub

Comments

Jonathan Wakely Jan. 27, 2023, 10:59 a.m. UTC | #1 
On Fri, 27 Jan 2023 at 09:29, Jakub Jelinek <jakub@redhat.com> wrote:
>
> Hi!
>
> On gcc112 which has glibc 2.17 I've noticed
> FAIL: 17_intro/names.cc (test for excess errors)
> FAIL: experimental/names.cc (test for excess errors)
> These are because glibc < 2.19 used __unused as field member of various structs,
> including mcontext_t in sys/ucontext.h on ppc64le.
> This was changed in glibc with
> https://gcc.gnu.org/pipermail/libc-alpha/2013-November/045766.html
> names.cc even has
> #ifdef __GLIBC_PREREQ
> #if ! __GLIBC_PREREQ(2, 19)
> // Glibc defines this prior to 2.19
> #undef __unused
> #endif
> #endif
> for it, but it doesn't work.  The reason is that __GLIBC_PREREQ is defined in
> <features.h> but nothing included that header before this spot (it is included later
> from bits/stdc++.h).
>
> The following patch on Linux/Hurd conditionally includes features.h to get
> the needed macros before deciding if __unused should be undefined or not.
> If needed, I could use __GLIBC_PREREQ then but would need to check if it is
> defined and between 1996 and 1999 it wasn't.
>
> Tested on powerpc64le-linux with glibc 2.17 (where it fixes the
> regressions), on x86_64-linux with glibc 2.35 (where it still PASSes),
> plus on the latter with -E -dD on the test to verify __unused is just
> defined and not undefined later on, ok for trunk?

OK, thanks.
diff mbox series

Patch

--- libstdc++-v3/testsuite/17_intro/names.cc.jj	2023-01-16 23:19:06.292716661 +0100
+++ libstdc++-v3/testsuite/17_intro/names.cc	2023-01-27 10:20:20.787645823 +0100
@@ -252,12 +252,15 @@ 
 #undef y
 #endif
 
-#ifdef __GLIBC_PREREQ
-#if ! __GLIBC_PREREQ(2, 19)
+#if defined (__linux__) || defined (__gnu_hurd__)
+#if __has_include(<features.h>)
+#include <features.h>
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 19
 // Glibc defines this prior to 2.19
 #undef __unused
 #endif
 #endif
+#endif
 
 #if __has_include(<newlib.h>)
 // newlib's <sys/cdefs.h> defines these as macros.