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
