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authorFlorian Weimer <fweimer@redhat.com>2024-05-18 09:33:19 +0200
committerFlorian Weimer <fweimer@redhat.com>2024-05-18 09:33:19 +0200
commit8d7b6b4cb27d4dec1dd5f7960298c1699275f962 (patch)
treed3233e6a49dbde86dee8ea46920714a1adbbddb7 /misc
parent2a99e2398d9d717c034e915f7846a49e623f5450 (diff)
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socket: Use may_alias on sockaddr structs (bug 19622)
This supports common coding patterns. The GCC C front end before version 7 rejects the may_alias attribute on a struct definition if it was not present in a previous forward declaration, so this attribute can only be conditionally applied. This implements the spirit of the change in Austin Group issue 1641. Suggested-by: Marek Polacek <polacek@redhat.com> Suggested-by: Jakub Jelinek <jakub@redhat.com> Reviewed-by: Sam James <sam@gentoo.org> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'misc')
-rw-r--r--misc/sys/cdefs.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 2e8279a..ab9620b 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -874,4 +874,13 @@ _Static_assert (0, "IEEE 128-bits long double requires redirection on this platf
# define __attribute_returns_twice__ /* Ignore. */
#endif
+/* Mark struct types as aliasable. Restricted to compilers that
+ support forward declarations of structs in the presence of the
+ attribute. */
+#if __GNUC_PREREQ (7, 1) || defined __clang__
+# define __attribute_struct_may_alias__ __attribute__ ((__may_alias__))
+#else
+# define __attribute_struct_may_alias__
+#endif
+
#endif /* sys/cdefs.h */