Re: $(foo) vs $(call foo)

[John Graham-Cumming]

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Stephan Beal wrote:
> is there a semantic difference between:
> 
>   foo:
>       $(my-macro)
> 
> and:
> 
>   foo:
>       $(call my-macro)

There's a slight performance penalty for doing $(call my-macro) instead
of $(my-macro), but it's very small.

If you like to walk on the wild side then there is another difference,
but I'm warning you that this difference is only for people who are
doing extreme things with GNU Make.

In this article http://www.cmcrossroads.com/content/view/6529/120/ I
talk about the fact that when you do $(call foo) the recursion checking
flag (that prevents you doing something like foo = $(foo)...) is reset.
 This means that you can make a variable refer to itself by doing
something like foo = $(call foo) (don't actually do that because you'll
crash GNU Make), but this did come in handy when I was making my GNU
Make Debugger project for reason discussed in the article above.

Again, that's only for people who like to play with fire.

John.

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