Re: Building cpan module that links with proprietary libs

[Andrew DeFaria <Andrew at DeFaria dot com>]

On 5/29/2014 1:29 AM, Csaba Raduly wrote:
> Hi Andrew,
>
> On Thu, May 29, 2014 at 4:12 AM, Andrew DeFaria  wrote:
> > I'm attempting to build a cpan module (well actually it's not a cpan module
> > but rather a module that uses MakeMaker and has the familiar perl
> > Makefile.PL, make, make test, make install installation procedure.
> > Additionally I need to link it to a set of proprietary libs that I am given
> > only the .lib files for. If you must know this is for Perforce's P4Perl
> > which I'd like to get working with Cygwin's Perl natively.
> >
> > I download the P4API bundle (the package that has include files and the .lib
> > files pre-compiled).
>
> The C++ P4 API is platform-specific; which platform did you choose?
> If it really contains .lib files (not .a), those are not recognized by
> Cygwin's gcc.

I had two archives two choose from. One was for Windows and contained 
the .lib files. The other was for Linux and contains .a files. I first 
tried the Linux one but that failed with:

g++  -shared P4.o  -o blib/arch/auto/P4/P4.dll lib/libp4.a      \
  /usr/lib/perl5/5.14/x86_64-cygwin-threads/CORE/cygperl5_14.dll 
-L/cygdrive/a/p4perlBuild/p4api/lib -lclient -lrpc -lsupp -lp4sslstub 
       \

collect2: error: ld terminated with signal 11 [Segmentation fault], core 
dumped
Makefile:531: recipe for target 'blib/arch/auto/P4/P4.dll' failed
make: *** [blib/arch/auto/P4/P4.dll] Error 1
Adefaria-lt:

I can give you more output if you need it.

Then I switched to the Windows archive that contained the .lib files.

I think the issue is that their Windows P4Perl build system uses Visual 
Studio to build and on Linux it uses g++. Their installation package is 
only for ActiveState. Supposedly at 5.18 ActiveState is changing to a 
g++ based backend using MingW I think so they'll eventually have to 
figure this out. Meantime I'm just trying to get it working under 
Cygwin's Perl...

> > Next I need to do:
> >
> > $ perl Makefile.PL --api-dir /.../path/to/unzipped/p4api
> >
> > This works fine and I procedure with the make. This fails with things like:
> >
> > make[1]: Leaving directory '/cygdrive/a/perl/P4Perl.Cygwin/lib'
> > g++ -c  -I/cygdrive/a/perl/p4api.windows/include/p4 -Ilib -x c++
> > -DUSEIMPORTLIB -O3   -DVERSION=\"2014.1\" -DXS_VERSION=\"2014.1\"
> > "-I/usr/lib/perl5/5.14/x86_64-cygwin-threads/CORE"
> > -DID_OS="\"CYGWIN17THREAD\"" -DID_REL="\"2014.1\"" -DID_PATCH="\"842847\""
> > -DID_Y="\"2014\"" -DID_M="\"05\"" -DID_D="\"06\"" -DOS_CYGWIN -DOS_CYGWIN17
> > -DOS_CYGWIN17THREAD -DOS_CYGWINTHREAD -DP4API_VERSION="515585"
> > -DID_API="\"2014.1/821990\"" P4.c
> > Running Mkbootstrap for P4 ()
> > chmod 644 P4.bs
> > rm -f blib/arch/auto/P4/P4.dll
> > g++  -shared P4.o  -o blib/arch/auto/P4/P4.dll lib/libp4.a      \
> >    /usr/lib/perl5/5.14/x86_64-cygwin-threads/CORE/cygperl5_14.dll        \
> >
> > P4.o:P4.c:(.text+0x45ac): undefined reference to `ClientApi::SetClient(char
> > const*)'
> > P4.o:P4.c:(.text+0x45ac): relocation truncated to fit: R_X86_64_PC32 against
> > undefined symbol `ClientApi::SetClient(char const*)'
> > P4.o:P4.c:(.text+0x4a9c): undefined reference to `ClientApi::SetHost(char
> > const*)'
> >
> > Notice that it removes P4.dll, so it seems to know it's working with dll's,
> > but then it calls g++ with a -o for libp4.a!
>
> No it doesn't. The argument to -o is blib/arch/auto/P4/P4.dll
> lib/libp4.a is the next input file.

Good catch! I missed that.

> What does the following say?
> nm lib/libp4.a | c++filt

Attached.

> > Meantime it fails with many undefined references. I think I might need to do
> > perl Makefile.PL with other opts to tell it that while it's using Cygwin and
> > can be very Linux-like, it needs to produce .dll's and not .a's or .o's.
>
> It seems to be on the right track; "g++ -shared -o P4.dll" sounds good to me.

Thanks for your help.
--
Andrew DeFaria
http://defaria.com

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