* tests/test-stddef.c: Add tests for offsetof.
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
I was about to push this, so we can detect any gotchas with using
offsetof according to POSIX. Then I decided to test first.
And the first loser is Solaris' /usr/bin/cc:
"../../gltests/test-stddef.c", line 44: syntax error before or at: &
"../../gltests/test-stddef.c", line 44: warning: syntax requires ";" after last
struct/union member
"../../gltests/test-stddef.c", line 44: zero-sized struct/union
"../../gltests/test-stddef.c", line 44: cannot recover from previous errors
cc: acomp failed for ../../gltests/test-stddef.c
Adding "redundant" parens to the sizeof(offsetof()) call fixed the
it for that compiler. Sure enough, /usr/include/iso/stddef_iso.h has:
#define offsetof(s, m) (std::size_t)(&(((s *)0)->m))
So before I push, I guess we need to beef up the stddef module
to detect and work around broken compilers/headers that don't
properly parenthesize their offsetof macro.
ChangeLog | 5 +++++
tests/test-stddef.c | 10 ++++++++++
2 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 86de94d..896557a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2010-08-16 Eric Blake <ebl...@redhat.com>
+
+ test-stddef: test offsetof compliance
+ * tests/test-stddef.c: Add tests for offsetof.
+
2010-08-15 Bruno Haible <br...@clisp.org>
stpncpy: Allow stpncpy to be defined as a macro.
diff --git a/tests/test-stddef.c b/tests/test-stddef.c
index d047e57..be8bc5e 100644
--- a/tests/test-stddef.c
+++ b/tests/test-stddef.c
@@ -31,6 +31,16 @@ size_t c = 2;
per POSIX 2008. */
verify (sizeof NULL == sizeof (void *));
+/* Check that offsetof produces integer constants with correct type. */
+struct d
+{
+ char e;
+ char f;
+};
+verify (sizeof offsetof (struct d, e) == sizeof (size_t));
+verify (offsetof (struct d, e) < -1); /* Must be unsigned. */
+verify (offsetof (struct d, f) == 1);
+
int
main (void)
{
--
1.7.2.1
