[Lazarus] How to access C and C++ libraries?

[Sven Barth]

On 06.03.2014 20:31, Chavoux Luyt wrote:
> Hi everybody!
>
> Years ago I used Delphi (on Windows) to access a C or C++ API (for
> talking directly with embedded device) and I can remember that there
> were a number of gotchas (e.g. the calling convention had to be changed
> form Pascal to something else (extern?) etc. ).
>
> Now I am wondering about writing a simple Lazarus GUI to the Telegram
> API (all C header files, AFAICT) on Linux (and maybe Windows, if not too
> difficult to port). Any gotchas to keep in mind for using C and C++
> libraries from Lazarus/Free Pascal (on Linux and maybe Windows) or good
> guides?

Basically: use cdecl calling convention (on Windows it *might* be 
stdcall though), do not use Pascal types like classes, strings, etc. for 
accessing the C API, better use the types in the ctypes unit instead.

Additional help is available here:

http://wiki.freepascal.org/Creating_bindings_for_C_libraries

Regards,
Sven