Getting Cocoa function from C++

Question

In the answer to this question: get logged in user the accepted answer uses Delphi code that looks like this to get access to the Cocoa function NSUserName.

function NSUserName: Pointer; cdecl; external '/System/Library/Frameworks/Foundation.framework/Foundation' name _PU +'NSUserName';

How would you do this in C++Builder?

Answer 1

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This answers the question and is worth the bounty

The solution is to import NSUserName in C++ by using dlopen and dlsym:

void* (*NSUserName)();
String UserName;
void *hLib = dlopen("/System/Library/Frameworks/Foundation.framework/Foundation", RTLD_GLOBAL);
if(hLib)
{
    NSUserName = (void*(*)())dlsym(hLib, "NSUserName");
    CFStringRef srUserName = (CFStringRef)NSUserName();
    if(srUserName)
    {
        UserName = CFStringGetCStringPtr(srUserName, 0);
    }
    dlclose(hLib);
}

It is possible to use NSString (Cocoa Type) directly in C++ Builder by adding a header file as:

#include <Macapi.Foundation.hpp> // note that this will cause 8080 warnings if you have this warning turned on (unused variables)

Now I can use NSString instead CFStringRef (Core Foundation Type):

UserName = TNSString::Wrap(NSUserName())->UTF8String();