[GAP Forum] Compiling GAP under Windows 2000 and mingw.

[Dima Pasechnik]

Dear Forum,
On Sun, Jan 30, 2005 at 05:33:20PM +0100, Sergio De Los Santos wrote:
> My intention is to build a Visual Basic Interface mainly to pacakage GUAVA. I'm not any expert in programming, but my idea is to build some DLL with C source and call functions from Visual Basic.
[...]
> I can't even compile it under Windows 2000 using mingw. I get lots of errors.
Certainly. Compiling with mingw will not differ from compiling using
a native Windows C compiler. Mingw does not know Posix, and 
GAP does not know anything about Win32 system calls;
it runs under Windows using Cygwin (not to be confused with mingw).
Cygwin takes the job of translating Posix system calls made by GAP
into Win32 calls.

While porting GAP to use native Win32 calls is doable, basically
src/system.c is the only place that needs lots of changes,
it is certainly a nontrivial and time-consuming task.
(and one needs to be a bit of an expert in programming to do this,
 IMHO)

Perhaps easier is to build GAP as a DLL, using Cygwin,
and call this DLL from VB.

Why would you insist on VB? Can you use something like XGAP instead?
It should be easier, and will run not only on Windows...

> I think once i get some dll files with the importan functions, to build an interface is not difficult at all. If it is impossible I would use pipes to pass parameters to gap.exe, but, first of all I would like to be able to build my own exe file.
> 
use Cygwin for this. After running configure, edit Makefile to replace
ocurrences of "strip gap" with "strip gap.exe". Then make will run
without errors.

HTH, 
Dmitrii