Can't find Xcode build setting - GCC_WARN_EFFECTIVE_CPLUSPLUS_VIOLATIONS - c++

Question

I'm using Xcode 6.2 to build a C++ command line application.
The Xcode Build Setting Reference states:
If you develop products using C++, you may need to customize these build settings in your targets:
GCC_WARN_EFFECTIVE_CPLUSPLUS_VIOLATIONS (Effective C++ Violation)
However this option does not appear in the build setting list for any of my targets.
Can anyone tell me where it is?

Answer 1

The setting in question no longer has any effect - if you place it into the pbxproj file, it appears as a user defined setting in the UI.
The setting only applies to the gnu g++ compiler, and xcode doesn't ship with that compiler any more (it ships with clang++ and a g++ wrapper that invokes clang++). a brief test of some conditions that trigger with g++ doesn't trigger with clang++ e.g.:
#include <string>
using std::string;
class foo {
string x;
int y;
void *ptr;
public:
foo() : y(1), ptr(0) {}
};
$ g++-4.9 -c -Weffc++ evil.cpp
evil.cpp:5:7: warning: 'class foo' has pointer data members [-Weffc++]
class foo {
^
evil.cpp:5:7: warning: but does not override 'foo(const foo&)' [-Weffc++]
evil.cpp:5:7: warning: or 'operator=(const foo&)' [-Weffc++]
evil.cpp: In constructor 'foo::foo()':
evil.cpp:11:5: warning: 'foo::x' should be initialized in the member initialization list [-Weffc++]
foo() : y(1), ptr(0) {}
^
$ clang++ -c -Weffc++ evil.cpp
$
There are opinions that it is too noisy to be useful - e.g. the complaint about not initializing x (a std::string) is a pointless warning in this situation, and as such is more trouble than it's worth.
You can manually add the -Weffc++ option to the compilation flags for C++ code, you can add it to the option Other C++ Flags, which is under Apple LLVM X.Y - Custom Compiler Flags (the X.Y depends on your version of XCode), but again the LLVM based compiler doesn't process that option.
It looks like the documentation is out of date for this option - I've logged a radar to have the option removed from the docs to prevent this confusion.