https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68689
Bug ID: 68689
Summary: flexible array members in unions accepted in C++
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
GCC (in C mode) rejects flexible array members in unions. G++ (i.e., in C++
mode) accepts them. Since flexible array members are a G++ extension provided
for compatibility with C, and specifically GCC, G++ should accept and reject
the same constructs as GCC does.
$ cat z.cpp && /build/gcc-trunk-svn/gcc/xg++ -B /build/gcc-trunk-svn/gcc -S
-Wall -Wextra -Wpedantic -o/dev/null z.cpp
union U {
int n;
int a[];
} u;
z.cpp:3:11: warning: ISO C++ forbids zero-size array ‘a’ [-Wpedantic]
int a[];
^
