How to catch C++ exception code in iOS Objective-C?

Question

I'm new to iOS programming, now I met a problem related to catching the exception code threw from a C++ class.

    @try {
        myCPPClass myObj ; //this throws integer exception codes
    }
    @catch (...) { //I want to catch the integer value here, how ??
        NSLog(@"Exception:") ;
    }
    @finally {
    } 

I knew it maybe not a good practice coding Objective-C in exception catching style, I'd like to know how to make custom exception class for C++ classes in Objective-C ?

Answer 1

Rename your objective-c .m source files to have the .mm extension. They will then be compiled as objective-c++ which is fully compatible with objective-c while offering all the facilities of c++.

then you can catch c++ exceptions with the usual

try {
   ...
}
catch(std::exception& e) {
   ...
}

construct.

Answer 2

An extension to Richard's answer for those still not catching any exceptions from C++.

Use this instead of try catch .

@try { } 
@catch (...) {
  NSLog(@"Exception:");
}

Why?

Objective-C catch clause taking a dynamically typed exception object (@catch(id exception)) can catch any Objective-C exception, but cannot catch any C++ exceptions. So, for interoperability, use @catch(...) to catch every exception and @throw; to rethrow caught exceptions. In 32-bit, @catch(...) has the same effect as @catch(id exception).

- C++ Interoperability

Still, not catching any exceptions?

• Don't specify the -no_compact_unwind flag.
• Specify the -funwind-tables flag if you're including plain C code.

- Addressing Language Exception Crashes