https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68489
Bug ID: 68489
Summary: arrays of flexible array members are silently accepted
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: ---
Related to bug 68478, g++ accepts definitions of C flexible array members as an
extension for compatibility. However, C doesn't intend to allow declaring
arrays of structures containing flexible array members. Such uses are rejected
by gcc (with a hard error), and diagnosed either as warnings (Clang) or hard
errors (IBM XLC++) in C++ programs.
However, as the test case below shows, g++ silently accepts such uses:
$ cat z.cpp && /build/gcc-trunk-svn/gcc/xg++ -B /build/gcc-trunk-svn/gcc -Wall
-Wextra -Wpedantic -O2 -S -o/dev/null z.cpp
struct A {
int n;
int a [];
};
struct A a[2]; // should be diagnosed/rejected
z.cpp:3:12: warning: ISO C++ forbids zero-size array ‘a’ [-Wpedantic]
int a [];
^
