macOS Newbie Xcode Link problem

[fredrum]

Hi All,

I am sure this is a really stupid question but if anyone can tell me what I might be doing wrong, I'd be really greatful.

I am using Xcode to try and compile an example included in a SDK. The sdk only uses one .a static library file and one header file.
Included is another .h file that "(no need to directly include this)"

In Xcode I made a C++ 'Command Line Utility'. The Build Config is set to 1386 archiotecture and Mac OS X 10.4 Base SDK.


It seems to me that it compiles ok but in the link phase I get the error message:

-------------------------------------------------------------------------------
Undefined symbols:
"_MPProcessors", referenced from:
REDCORE:AL::GetNumberOfProcessors() in R3DSDKv1.a(R3DSDKv1.a-i386-master.o)
ld: symbol(s) not found
collect2: ld returned 1 exit status
-------------------------------------------------------------------------------


But I can't find any of the above in the .h file or the short .cpp file.


Would anyone be able to guess what might be going on here?



cheers
fred

 

[gnasher729]

It seems to me that it compiles ok but in the link phase I get the error message:

-------------------------------------------------------------------------------
Undefined symbols:
"_MPProcessors", referenced from:
REDCORE:AL::GetNumberOfProcessors() in R3DSDKv1.a(R3DSDKv1.a-i386-master.o)
ld: symbol(s) not found
collect2: ld returned 1 exit status

It looks like the library you are using uses a function that is not part of your programming. Most likely it is in one of the frameworks that come with the operating system; otherwise that SDK would have never worked. So here is what you do:

1. What is the name of the function that is missing? The linker tells you: It is MPProcessors.

2. In which header file is it declared? Do Command-Space, type in MPProcessors, Spotlight finds a few files, and eventually you figure out it is in Multiprocessing.h.

3. If you open the file and look where it is located (Command-click on the window title), you find it is within the CarbonCore framework inside the CoreServices framework.

4. Add the Framework: Add to project, then go to your hard drive -> System -> Library -> Frameworks and pick the CoreServices framework.

 

[fredrum]

Wicked!! Thank you very much Sir for that brilliant answer!

It went through the build fine after adding 'CodeServices' as you said.
And I learned a bit of problem solving, as an extra bonus.
Can now go to sleep.

cheers
fred