Objective-C++ executable file compilation (with .mm) - xcode

Question

Intro. I am facing a strange error with Objective-C++. All my files are of the correct type (.h/.mm instead of .hpp/.cpp). I use clib++ (built into xCode of latest version on macOS Sierra, but it was the same way on El Capitan) instead of libstd++ (that is older and doesn't fully support even C++11).
The problem. I can't compile template classes with both header and executable files. Only in case if entire code is written in header!
However, if I make a non-template class it works just fine even when split into 2 files. Header:
class TempClass {
public:
TempClass(int x);
~TempClass() {};
};
Executable:
TempClass::TempClass(int x) {}
Template class code. Header:
template <typename T> class TempClassTemplate {
public:
TempClassTemplate(T v);
~TempClassTemplate() {};
T val;
};
Executable:
template<typename T> TempClassTemplate<T>::TempClassTemplate(T v) : val(v) {};
Usage example, that causes crash:
int main(int argc, char * argv[]) {
auto obj = new TempClass(5);
printf("temp size is %lu\n", sizeof(obj));
auto objV = new TempClassTemplate<int>(10);
printf("temp size is %lu, val is %i\n", sizeof(objV), objV->val);
#autoreleasepool {
return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
}
}
Results:

Answer 1

The problem isn't with Objective-C or Objective-C++. Its pure C++ known issue, but the compiler gives not enough info.
You can only make a template class - header only. But there are some walkarounds. Read this article for full answer: http://www.codeproject.com/Articles/48575/How-to-define-a-template-class-in-a-h-file-and-imp
But the short and simple solution is to write all the possible template class usages in the end of .cpp/.mm file like this:
template class TempClassTemplate<int8_t>;
template class TempClassTemplate<int16_t>;
template class TempClassTemplate<int32_t>;