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Re: Building cpan module that links with proprietary libs

On 5/29/2014 6:42 PM, Larry Hall (Cygwin) wrote:

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      \
-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

I can give you more output if you need it.

No need.  Forgive me for saying this but I find it hard to believe that
after all this time on the list Andrew that you don't know that trying to
use Linux-compiled libraries on Cygwin isn't going to work.  But I guess
my surprise is not that important here. ;-)

When I first when to get this to work I choose the Linux style of the package for p4api. I figured the Windows style was for ActiveState only and that'd probably not work. Hell ActiveState doesn't even use cpan, they use ppm. I didn't look inside for anything like .o, .a or .dll or .lib. I figured that it would have been source code and it would have been compiled as part of the make process. It wasn't until it failed that I saw the reference to .a's, etc. and looked into the p4api directory structure to see .lib's in the Windows copy and .a's in the Linux copy. Sure at *that* point I knew the Linux style will never work in this situation. So I tried to link with the Windows style .lib copy.

It seems to be on the right track; "g++ -shared -o P4.dll" sounds
good to me.

You say that the libs were built by Visual Studio and the remainder of your
comments make it clear that the libraries are C++ and not C code.

I don't believe I ever said it was just C code. If I did then I'm sorry.

As a
result, you will never get code compiled with g++ to link with these
libraries.  There is no common ABI among C++ compilers.  Thus, the
and headers of one can't be used as input to the compiler of another, even
on the same platform.  This only works for C code.  So you have to either
build the proprietary libs with Cygwin's C++ compiler or write your own
"shim" library that wraps the necessary calls and objects in a C API,
compile that with VS, and link your program against the APIs in your

Being as this code is proprietary I doubt that Perforce will release it to me to compile but I will point them at this thread...'

Andrew DeFaria

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