> ----- Original Message ----- > From: Daniel Brendle <grindh...@skarphed.org> > Sent: Monday, 5 December 2016, 7:53 > Subject: [Vala] VAPI-Bindings to obscure c-types.
> In libode's code, there is a type called dReal. Depending on some > compiler flags, dReal might be a double or a float: > #if defined(dSINGLE) > typedef float dReal; > #ifdef dDOUBLE > #error You can only #define dSINGLE or dDOUBLE, not both. > #endif /* dDOUBLE */ > #elif defined(dDOUBLE) > typedef double dReal; > #else > #error You must #define dSINGLE or dDOUBLE > #endif > The library then uses dReal in various method signatures that I have to > bind against. Is there any possibility to cover this in vala? These are macros that are defined without a value and are used by the C pre-processor. To define such a macro from valac, as you probably know, you use the -X option: valac --pkg libode6 -X -DdDOUBLE example.vala Vala has a similiar, but much simpler, pre-processor: https://wiki.gnome.org/Projects/Vala/Manual/Preprocessor https://wiki.gnome.org/Projects/Vala/ConditionalCompilationSample The Vala pre-processor can also be used in a VAPI file: #if ODE_FLOAT [SimpleType] [CCode (cname = "dReal", has_type_id = false)] public struct dReal : float { } #else [SimpleType] [CCode (cname = "dReal", has_type_id = false)] public struct dReal : double { } #endif So for double you would compile with: valac --pkg libode6 -X -DdDOUBLE example.vala and for float: valac --pkg libode6 -X -DdSINGLE -D ODE_FLOAT example.vala You will have to use separate declarations for both the C pre-processor and the Vala pre-processor. While you can define a macro in a .vala file by using const, this cannot currently be emitted before the #include in the generated C file. So it is not set at the time when the C header is processed. This is untested and probably doesn't reflect your binding, but should convey the method. Al _______________________________________________ vala-list mailing list vala-list@gnome.org https://mail.gnome.org/mailman/listinfo/vala-list
