Re: Creating a block using the Macros....

[David Chisnall]

This is not possible in the general case.

A block is a structure containing:

 - A pointer to the invoke function.
 - The type info for the call.
 - A set of references to captured variables including:
   - Helpers to destroy any captured variables.
   - Helpers to copy any captured variables.

C macros are nowhere near expressive enough for this.  You could 
probably (just about) implement them using C++ templates, though it 
would be a lot of work.

The block macros give a way of allowing functions / methods that take 
blocks to be called, so that it is possible to build GNUstep with GCC 
and link it to a program built with clang.  To date, anything that needs 
to create blocks, we have implemented a different way or conditionally 
compiled out when building with GCC.

David

On 27/10/2019 15:55, Gregory Casamento wrote:
> How do I create a block using the macros?  I know how to declare one, 
> but not actually create one.   Doing it in clang is easy, but I need 
> something that will work for both....
>
> Any ideas?
>
> GC
> --
> Gregory Casamento
> GNUstep Lead Developer / OLC, Principal Consultant
> http://www.gnustep.org - http://heronsperch.blogspot.com
> http://ind.ie/phoenix/
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> 10/27/19, 11:53:53 AM