Menno Schaap wrote:
Maybe, but it is for a company. And I think it is no problem for them to pay. It will be non open source, non-free software. Do you know how this works in according with GCC, GPC an GTK+ (GPL?).
GCC and GPC are no problem. The GPL explicitly states that "the output from the Program is covered only if its contents constitute a work based on the Program" which is not the case for the compilers.
The GPC runtime system also does not pose restrictions on your program's license. Same goes for most of GPC's units, exceptions are GMP, rx (LGPL) and MD5 (GPL).
You can link LGPL'ed libraries to non-GPL'ed programs under a few conditions (see COPYING.LIB).
So, if GTK+ is GPL, you can't use it in your program, if it's LGPL, you can if you respect those conditions.
Frank