Re: MinGW build fixes

[Neil Jerram]

"carlo.bramix" <address@hidden> writes:

> Hello!

Hi Carlo!

>>> I don't understand why this fixes anything, since the `_ptr'
>>> variables are declared as `SCM_API' just like the non-`_ptr'
>>> variables.
>>  Indeed.  My guess is that it's because the DLL import/export
>> mechanism works for atomic data - i.e. chars, ints, pointers etc -
>> but not for structs.
>
> False.  A DLL can export functions, variables, structures, unions and
> classes.  After few fixes that I'm preparing to share, guile already
> compiles and it works perfectly in cygwin, which uses DLL too:

Great!  I know there are already several emails from you that I
haven't responded to yet; please be assured that I do plan to.

> although it virtualizes a lot, cygwin cannot do miracles, it's always
> windows based and if you add -mno-cygwin it becames identical to
> mingw.

I think you mean when compiling in Cygwin, and that the -mno-cygwin is
a GCC flag; is that right?

>  What we could suspect about it is the implementation of
> -export-dynamic under your mingw: which version are you using?

I'm using the MinGW cross compiler on GNU/Linux (Debian lenny):

address@hidden:~$ i586-mingw32msvc-gcc --version
i586-mingw32msvc-gcc (GCC) 4.2.1-sjlj (mingw32-2)

The configure invocation is:

    CPPFLAGS=-I/usr/local/i586-mingw32msvc/include \
    LDFLAGS=-L/usr/local/i586-mingw32msvc/lib \
    GUILE_FOR_BUILD=/usr/local/bin/guile \
    ./configure --prefix=/usr/local/i586-mingw32msvc --host=i586-mingw32msvc

You can see the logs of my builds, for the Guile master and
branch_release-1-8 branches, at
http://www.ossau.uklinux.net/guile/snapshots, or at
http://autobuild.josefsson.org/guile/.

>  I'm
> using the latest maintenance releases of gcc 3.4.5 and binutils
> 2.18.50 without troubles.  Actually the troubles with mingw are
> elsewhere... may I ask how you made it working?  Unless it has been
> committed recently, guile cannot be even compiled well because it is
> missing the support for CreateFileMapping(), plus other fixes around
> the code!

What version of Guile have you been trying to build?  My attempt to
build the master branch (i.e. similar to the 1.9.0 pre-release)
currently fails at

./guile-snarf -o objcodes.x objcodes.c -DHAVE_CONFIG_H -DBUILDING_LIBGUILE=1 
-I.. -I.. -I../lib -I../lib -I/usr/local/i586-mingw32msvc/include -g -O2
objcodes.c:26:22: error: sys/mman.h: No such file or directory

which I guess might be the same problem as "missing the support for
CreateFileMapping".

The branch_release-1-8 branch (i.e. similar to 1.8.x releases) seems
fine. though.

>  Are you using another posix compatibility layer? But I
> could not see any change in your patch for configure script...

I hope my answers above cover this; let me know if not.

> Anyways, I would not corrupt guile because an isolated compiler bug
> (my opinion).

Worst case is that I'll put the MinGW changes in #ifdef __MINGW32__.
That's still corruption in a sense, but only a very little.

Regards,
        Neil