Currently g++ requires the -pedantic flag to give a warning on a zero sized
array that is not the last field in a struct. As far as I can see, this is
actually always a significant error if it is not the trailing field in the
struct...
Demonstration:
temp(510)$ cat zero-size-array.cpp
#include <iostream>
#include <cstddef>
struct bogus
{
int a;
char b[];
int c;
} bogus;
int main(void)
{
std::cout << "size of struct bogus =" << sizeof(bogus) << std::endl;
std::cout << "offset of field b =" << offsetof(struct bogus, b) <<
std::endl;
std::cout << "offset of field c =" << offsetof(struct bogus, b) <<
std::endl;
return 0;
}
temp(511)$ g++ -Wall -o zero-size-array
zero-size-array.cppsize-array.cppe-array.cpp
temp(512)$ zero-size-array
size of struct bogus =8
offset of field b =4
offset of field c =4
temp(513)$ g++ -Wall -pedantic -o zero-size-array
zero-size-array.cppize-array.cpp
zero-size-array.cpp:7: error: ISO C++ forbids zero-size array 'b'
temp(514)$ g++ --version
g++ (GCC) 4.1.2 20070626 (Red Hat 4.1.2-14)
-David
--
Summary: g++ should warn or error on internal 0 size array in
struct
Product: gcc
Version: 4.1.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: david dot resnick at comverse dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42121
