Re: mingw vs cygwin

[Jeffrey Creem <jeff@thecreems.com>]

midgleyben@hotmail.com wrote:
> I have a question about the differences between cygwin adn mingw, with
> reference to the ada compiler.
> 
> I need to port ada code to XP from linux, link c code (maybe c++) to
> the project and create an exe which supports sockets (networking). So
> which way mingw or cygwin ? I have read so many reports of problems
> with c under mingw and just problems with gcc-ada but non particularly
> up to date, any advice welcome.
> 
> Also if I get the whole cygwin installation I get mingw too, to my
> understanding if I use mingw I statically link support for the windows
> API and if I use the gcc-ada compiler I need to provide cygwin1.dll for
> distribution, is this accurate and can anyone add detail to this
> explanation ? 
> 
> Thanks in advance
> 

If you go to any "help" newsgroup you will find nothing but problems 
about a topic so first of all I would not get too worked up about seeing 
"nothing but problems" with people doing C under mingw.

Next, you do not need to provide cygwin1.dll for Ada code that is built 
from a mingw based distribution.

The question is, do you need capability that is present in the cygwin 
dll or not. The cygwin dll provides essentially a unix compatibility 
layer. Depending on the nature of your code, you might not need it at all.

If you do think you need it, you need to understand the licensing terms 
of the cygwin dll which is essentially (last time I checked) GPL (not 
LGPL). (Though I think you can buy a license under different terms from 
Redhat).

If you need to link your code against the standard cygwin dll then you 
will need to distribute your application under the terms of the dll 
(read the GPL for details. Short story, you have to give the source code 
to everyone you give the binary to and you can't limit who they give the 
source code to).


The standard AdaCore GNAT build executables that are mingw based. The 
cygwin.dll that is inside of most of the GNAT windows binary 
distributions is there (I think) to support the GDB install which is 
cygwin based.


In general, I would not recommend the cygwin approach unless it is 
critical to a successful port.