https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68490
Bug ID: 68490
Summary: error initializing a structure with a flexible array
member
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: ---
g++ accepts definitions of flexible array members as an extension for
compatibility with C. In C mode, as an extension, gcc and compatible compilers
accept initialized definitions of objects of structures containing flexible
array members, provided such objects have static storage duration. Some of the
compatible compatible (Clang) also accept the extension in C++ mode.
However, as the test case below shows, g++ rejects such uses. Since flexible
array members are accepted by g++ for compatibility with C (most notably gcc),
it seems that the initialized definitions should be accepted by g++ as well.
$ 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 foo (void)
{
static struct A a = { 2, { 1, 0 } };
return a;
}
z.cpp:3:12: warning: ISO C++ forbids zero-size array ‘a’ [-Wpedantic]
int a [];
^
z.cpp: In function ‘A foo()’:
z.cpp:8:39: error: too many initializers for ‘int [0]’
static struct A a = { 2, { 1, 0 } };
^
