Re: [Vala] Conditional compilation: Passing #ifdefs through to generated C code

[Levi Bard <taktaktaktaktaktaktaktaktaktak gmail com>]

> I'd like to know more about how to use C preprocessor commands in
> Vala.  I know that Vala allows some sort of conditional compilation
> via [Conditional], but I'm interested in a particular use case that it
> doesn't seem to really help with.
>
> Specifically, I have a GTK+ app, and I want to use a bit of code only
> if the compile-time GTK+ version is high enough.  So something like:
>
> #if GTK_CHECK_VERSION(2, 4, 0)
>    GtkFileChooserAction action;
>    ...
> #endif
>
> I can have vala conditionally use a bit of code, but the conditional
> is resolved at Vala-compile-time, not C-compile-time.  I need
> 'passthrough' conditionals that show up in the generated C code, since
> my software distributes the C code in the release tarball.  The
> typical user just compiles the C.

2 suggestions:
1) Isolate the conditional code in a C glue file.
2) Use the build system to resolve the condition. (e.g. Automake conditionals)


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