Bug#469512: Attribute warn_unused_result ignored on function returning union

[Goswin Brederlow <goswin-v-b@web.de>]

Package: g++-4.1
Version: 4.1.1-21
Severity: normal

Hi,

I work without execptions and want to ensure that error codes that
might be returned by functions will not be ignored. So I added the
attribute warn_unused_result to the function prototype. But with
functions returning an union the attribute is ignored:

------------------------[ foo.c / foo.cc ]----------------------------
union Error { int error; void* val; };
Error foo(void) __attribute__ ((warn_unused_result));
int bar(void) __attribute__ ((warn_unused_result));
void baz(void) { foo(); bar(); }
----------------------------------------------------------------------
% g++ -W -Wall -O2 -c foo.cc
foo.cc: In function 'void baz()':
foo.cc:4: warning: ignoring return value of 'int bar()', declared with attribute warn_unused_result
----------------------------------------------------------------------
% gcc -W -Wall -O2 -c foo.c 
foo.c: In function 'baz':
foo.c:4: warning: ignoring return value of 'foo', declared with attribute warn_unused_result
foo.c:4: warning: ignoring return value of 'bar', declared with attribute warn_unused_result
----------------------------------------------------------------------

MfG
	Goswin

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Versions of packages g++-4.1 depends on:
ii  gcc-4.1                     4.1.1-21     The GNU C compiler
ii  gcc-4.1-base                4.1.1-21     The GNU Compiler Collection (base 
ii  libc6                       2.3.6.ds1-13 GNU C Library: Shared libraries
ii  libstdc++6-4.1-dev          4.1.1-21     The GNU Standard C++ Library v3 (d

g++-4.1 recommends no packages.

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