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Re: ld: common symbols not allowed with MH_DYLIB output format with the -multi_module option

On Jun 10, 2005, at 3:45 PM, Mike Stump wrote:

I'd put this more simply...

On Monday, June 6, 2005, at 02:06 PM, Mathieu Malaterre wrote:
I have a question about a valid C code. I am trying to compile the following code in MacOSX (*). I don't understand what the problem is?

You must use -fno-common when you are building dynamic libraries on darwin.

Could someone please explain me what is going on?

You didn't use -fno-common.

Can someone please tell me then which one of the three possibilities is the right one:

#1. I need to tell the linker to use -single_module
#2. Rewrite the code to make a fake initialization
#3. I need to pass -fno-common to the compiler

I really don't understand why I need to do that, since this is valid C code. Why the linker does not default to proper option, or why the -fno-common option isn't used. At compile time gcc should figure that out, right ?

Now compared to the linker option, at least the compiler flag I can specify it for the specific file I want, which is great. But then again why is this up to the user to do it ? Is there a performance reason ? Why isn't it the default ?

How do other people do when porting *nix lib to MacOSX ? Is this is trial-and-error process to get the lib compiled ?


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