$ cat testunion.cpp
// testunion.cpp
static union { struct n { int I2; } S2; }; // Case 1
static union { struct { int I1; } S1; }; // Case 2
struct foo
{
union { struct n { int I2; } S2; }; // Case 3
union { struct { int I1; } S1; }; // Case 4
};
void func()
{
union { struct n { int I2; } S2; }; // Case 5
union { struct { int I1; } S1; }; // Case 6
}
$ g++ --version
g++ (GCC) 3.4.4 (cygming special) (gdc 0.12, using dmd 0.125)
Copyright (C) 2004 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ g++ -c -pedantic testunion.cpp
testunion.cpp:8: error: `struct foo::<anonymous union>::n' invalid; an
anonymous
union can only have non-static data members
g++ reports an error only in Case 3, regardless of the settings of -pedantic or
-pedantic-errors, but as I understand it all six cases violate the C++
standard. Accordingly, Comeau and xlc++ reject all six cases in strict mode,
and accept them with warnings in relaxed mode.
This behavior is consistent for at least versions 3.4.4 and 3.3.2.
--
Summary: ISO compliance of defining structs in anonymous unions
Product: gcc
Version: 3.4.4
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: cfranz at aldon dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25322
