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* [Bug c/44692] New: Ambiguous member names in anonymous struct/union does not error
@ 2010-06-27 18:20 mark-gcc at pogo dot org dot uk
2010-06-27 18:22 ` [Bug c/44692] " mark-gcc at pogo dot org dot uk
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: mark-gcc at pogo dot org dot uk @ 2010-06-27 18:20 UTC (permalink / raw)
To: gcc-bugs
The manual:
http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html
states that the compiler gives an error for constructs which are ambigious.
However I could not produce this error, even using the example on that page:
struct {
int a;
struct {
int a;
};
} foo;
I was first made aware of this with a structure like the following. This also
does not produce any compiler error, either at definition or where member
variables are used:
union {
int a;
struct {
int x;
int a;
};
} bar;
Instead, where 'a' is used, the first definition is seen to be used, silently
with no error or warning. This is more serious, because use of x overwrites a.
Test platform is GCC 4.5.0 (Arch Linux), building with -Wall. Also verified on
GCC 4.3.3 (Slackware Linux)
vega$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-pc-linux-gnu/4.5.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../configure --prefix=/usr
--enable-languages=c,c++,fortran,objc,obj-c++,ada --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
--enable-gnu-unique-object --enable-lto --enable-plugin --disable-multilib
--disable-libstdcxx-pch --with-system-zlib --with-ppl --with-cloog
--libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info
Thread model: posix
gcc version 4.5.0 20100610 (prerelease) (GCC)
--
Summary: Ambiguous member names in anonymous struct/union does
not error
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: mark-gcc at pogo dot org dot uk
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44692
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c/44692] Ambiguous member names in anonymous struct/union does not error
2010-06-27 18:20 [Bug c/44692] New: Ambiguous member names in anonymous struct/union does not error mark-gcc at pogo dot org dot uk
@ 2010-06-27 18:22 ` mark-gcc at pogo dot org dot uk
2010-06-27 18:22 ` mark-gcc at pogo dot org dot uk
2010-06-27 18:32 ` jsm28 at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: mark-gcc at pogo dot org dot uk @ 2010-06-27 18:22 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from mark-gcc at pogo dot org dot uk 2010-06-27 18:22 -------
Created an attachment (id=21019)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21019&action=view)
Preprocessed source code
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44692
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c/44692] Ambiguous member names in anonymous struct/union does not error
2010-06-27 18:20 [Bug c/44692] New: Ambiguous member names in anonymous struct/union does not error mark-gcc at pogo dot org dot uk
2010-06-27 18:22 ` [Bug c/44692] " mark-gcc at pogo dot org dot uk
@ 2010-06-27 18:22 ` mark-gcc at pogo dot org dot uk
2010-06-27 18:32 ` jsm28 at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: mark-gcc at pogo dot org dot uk @ 2010-06-27 18:22 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from mark-gcc at pogo dot org dot uk 2010-06-27 18:22 -------
Created an attachment (id=21018)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21018&action=view)
Example program
Source code, compile and test with:
gcc -Wall anon.c && ./a.out
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44692
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c/44692] Ambiguous member names in anonymous struct/union does not error
2010-06-27 18:20 [Bug c/44692] New: Ambiguous member names in anonymous struct/union does not error mark-gcc at pogo dot org dot uk
2010-06-27 18:22 ` [Bug c/44692] " mark-gcc at pogo dot org dot uk
2010-06-27 18:22 ` mark-gcc at pogo dot org dot uk
@ 2010-06-27 18:32 ` jsm28 at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: jsm28 at gcc dot gnu dot org @ 2010-06-27 18:32 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from jsm28 at gcc dot gnu dot org 2010-06-27 18:31 -------
That documentation is for current development sources, where those errors
are given. Note that
http://gcc.gnu.org/onlinedocs/gcc-4.5.0/gcc/Unnamed-Fields.html
has different wording.
--
jsm28 at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44692
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-06-27 18:32 UTC | newest]
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2010-06-27 18:20 [Bug c/44692] New: Ambiguous member names in anonymous struct/union does not error mark-gcc at pogo dot org dot uk
2010-06-27 18:22 ` [Bug c/44692] " mark-gcc at pogo dot org dot uk
2010-06-27 18:22 ` mark-gcc at pogo dot org dot uk
2010-06-27 18:32 ` jsm28 at gcc dot gnu dot org
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