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[Bug c++/85601] New: [8 Regression] anonymous struct & union namespace conflict in extern C block
- From: "andres at anarazel dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 02 May 2018 00:01:50 +0000
- Subject: [Bug c++/85601] New: [8 Regression] anonymous struct & union namespace conflict in extern C block
- Auto-submitted: auto-generated
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85601
Bug ID: 85601
Summary: [8 Regression] anonymous struct & union namespace
conflict in extern C block
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: andres at anarazel dot de
Target Milestone: ---
Hi,
When compiling with g++ anonymous structs / unions inside C functions conflict
based on their variable name. That wasn't previously the case and doesn't seem
to make much sense.
Ex.:
extern "C"
{
static inline void funca(void)
{
union
{
int a;
} myunion;
(void) myunion;
}
static inline void funcb(void)
{
union
{
int a;
} myunion;
(void) myunion;
}
}
andres@alap4:~/src/postgresql$ /usr/lib/gcc-snapshot/bin/g++ --version
g++ (Debian 20180425-1) 9.0.0 20180425 (experimental) [trunk revision 259645]
..
andres@alap4:~/src/postgresql$ /usr/lib/gcc-snapshot/bin/g++ -c -o /tmp/frak.o
/tmp/frak.cc
/tmp/frak.cc: In function 'void funcb()':
/tmp/frak.cc:18:9: warning: conflicting C language linkage declaration
'funcb()::<unnamed union> myunion'
} myunion;
^~~~~~~
/tmp/frak.cc:8:9: note: previous declaration 'funca()::<unnamed union> myunion'
} myunion;
^~~~~~~
If I rename one of the *variables* in the *independent* functions the error
vanishes.
This currently triggers inside PostgreSQL's master branch (which now uses C++
for an optional module).
Regards,
Andres Freund