problem linking my C++ class to my C static library .a on iphone xcode

Question

Hi all,

I have a problem linking with a .a C static library I have compiled as a separate target.

My library is called libtest.a and has only one function: int test() which returns 1 always. I have put libtest.a and test.h (its header file) in a mylibrary_directory

Then I create a new iphone view base project and added mylibrary_directory to the library search path, the header search path and the user headers search paths in xcode. Also I have added the -ltest flag in other linker flags option.

When I make calls to test() in myProjectViewController.m it WORKS

- (void)viewDidLoad {
   [super viewDidLoad];
   test();
   }

So far so good. But the problem occurs when I create a new C++ class in my project making calls to test(). Then the linker complains that the symbol _test() is not found and the projetc does NOT build.

myClass.h:

#import "test.h"

class myClass
{
 int testCall();

}

myClass.mm:

int myClass::testCall()
{
  return test();
}

I get:

Undefined symbols:

  "test()", referenced from:
      myClass::testCall()     in myClass-64D20670AC6C3193.o
   ld: symbol(s) not found
   collect2: ld returned 1 exit status

The Ld command output does show the correct -ltest and -Lcorrect_paths

My guess is that I am missing some flags either when I compile my library or in myProject. Any ideas or help?

Thanks

Baba.

Answer 1

C++ name mangling is getting you, probably. Make sure you mark your declarations of test() extern "C" wherever C++ can see them.