ld under cygwin unable to find libs that exist

Question

I'm trying to install p4python, a Python extension for the Perforce revision control system. I'm using cygwin to accomplish this as p4python requires the P4 C++ API (it's really just a wrapper), which in turn requires g++ (not to mention, Python extensions require a C compiler, hence, gcc). I'm on Windows 7 64-bit (not by choice) and Microsoft VS 2008 gave me some pretty stubborn problems; I had heard that using Cygwin/MinGW might be a better route. I also looked for related questions and none of them seemed to have a particularly relevant answer.

The best I can think of is that ld is looking in the wrong place for these libs and I'm told that Cygwin doesn't handle symbolic links very well, but I'm not sure where to go from here. See terminal output below:

API Release 2010.2
running install
running build
running build_py
running build_ext
building 'P4API' extension
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DID_OS="CYGWINX86" -DID_REL="2009.2" -DID_PATCH="240822" -DID_API="2010.2" -DID_Y="2010" -DID_M="04" -DID_D="02" -IC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -IC:\Pyt
hon\p4api\p4api-2010.2.295040-vs2010_static\/include/p4 -I/usr/include/python2.6 -c P4API.cpp -o build/temp.cygwin-1.7.9-i686-2.6/P4API.o -DOS_CYGWIN -DOS_CYGWIN -DOS_CYGWINX86 -DOS_CYGWINX86
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for Ada/C/ObjC but not for C++
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DID_OS="CYGWINX86" -DID_REL="2009.2" -DID_PATCH="240822" -DID_API="2010.2" -DID_Y="2010" -DID_M="04" -DID_D="02" -IC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -IC:\Pyt
hon\p4api\p4api-2010.2.295040-vs2010_static\/include/p4 -I/usr/include/python2.6 -c PythonClientAPI.cpp -o build/temp.cygwin-1.7.9-i686-2.6/PythonClientAPI.o -DOS_CYGWIN -DOS_CYGWIN -DOS_CYGWINX86 -DOS_CYGWINX86
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for Ada/C/ObjC but not for C++
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DID_OS="CYGWINX86" -DID_REL="2009.2" -DID_PATCH="240822" -DID_API="2010.2" -DID_Y="2010" -DID_M="04" -DID_D="02" -IC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -IC:\Pyt
hon\p4api\p4api-2010.2.295040-vs2010_static\/include/p4 -I/usr/include/python2.6 -c PythonClientUser.cpp -o build/temp.cygwin-1.7.9-i686-2.6/PythonClientUser.o -DOS_CYGWIN -DOS_CYGWIN -DOS_CYGWINX86 -DOS_CYGWINX86
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for Ada/C/ObjC but not for C++
PythonClientUser.cpp: In member function ‘virtual int PythonClientUser::Resolve(ClientMerge*, Error*)’:
PythonClientUser.cpp:423: warning: deprecated conversion from string constant to ‘char*’
PythonClientUser.cpp:423: warning: deprecated conversion from string constant to ‘char*’
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DID_OS="CYGWINX86" -DID_REL="2009.2" -DID_PATCH="240822" -DID_API="2010.2" -DID_Y="2010" -DID_M="04" -DID_D="02" -IC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -IC:\Pyt
hon\p4api\p4api-2010.2.295040-vs2010_static\/include/p4 -I/usr/include/python2.6 -c SpecMgr.cpp -o build/temp.cygwin-1.7.9-i686-2.6/SpecMgr.o -DOS_CYGWIN -DOS_CYGWIN -DOS_CYGWINX86 -DOS_CYGWINX86
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for Ada/C/ObjC but not for C++
SpecMgr.cpp: In member function ‘PyObject* SpecMgr::NewSpec(StrPtr*)’:
SpecMgr.cpp:550: warning: deprecated conversion from string constant to ‘char*’
SpecMgr.cpp:550: warning: deprecated conversion from string constant to ‘char*’
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DID_OS="CYGWINX86" -DID_REL="2009.2" -DID_PATCH="240822" -DID_API="2010.2" -DID_Y="2010" -DID_M="04" -DID_D="02" -IC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -IC:\Pyt
hon\p4api\p4api-2010.2.295040-vs2010_static\/include/p4 -I/usr/include/python2.6 -c P4Result.cpp -o build/temp.cygwin-1.7.9-i686-2.6/P4Result.o -DOS_CYGWIN -DOS_CYGWIN -DOS_CYGWINX86 -DOS_CYGWINX86
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for Ada/C/ObjC but not for C++
P4Result.cpp: In destructor ‘P4Result::~P4Result()’:
P4Result.cpp:49: warning: suggest explicit braces to avoid ambiguous ‘else’
P4Result.cpp:52: warning: suggest explicit braces to avoid ambiguous ‘else’
P4Result.cpp:55: warning: suggest explicit braces to avoid ambiguous ‘else’
P4Result.cpp: In member function ‘void P4Result::Reset()’:
P4Result.cpp:71: warning: suggest explicit braces to avoid ambiguous ‘else’
P4Result.cpp:75: warning: suggest explicit braces to avoid ambiguous ‘else’
P4Result.cpp: In member function ‘void P4Result::Fmt(const char*, PyObject*, StrBuf&)’:
P4Result.cpp:189: warning: deprecated conversion from string constant to ‘char*’
P4Result.cpp:189: warning: deprecated conversion from string constant to ‘char*’
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DID_OS="CYGWINX86" -DID_REL="2009.2" -DID_PATCH="240822" -DID_API="2010.2" -DID_Y="2010" -DID_M="04" -DID_D="02" -IC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -IC:\Pyt
hon\p4api\p4api-2010.2.295040-vs2010_static\/include/p4 -I/usr/include/python2.6 -c PythonMergeData.cpp -o build/temp.cygwin-1.7.9-i686-2.6/PythonMergeData.o -DOS_CYGWIN -DOS_CYGWIN -DOS_CYGWINX86 -DOS_CYGWINX86
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for Ada/C/ObjC but not for C++
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DID_OS="CYGWINX86" -DID_REL="2009.2" -DID_PATCH="240822" -DID_API="2010.2" -DID_Y="2010" -DID_M="04" -DID_D="02" -IC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -IC:\Pyt
hon\p4api\p4api-2010.2.295040-vs2010_static\/include/p4 -I/usr/include/python2.6 -c P4MapMaker.cpp -o build/temp.cygwin-1.7.9-i686-2.6/P4MapMaker.o -DOS_CYGWIN -DOS_CYGWIN -DOS_CYGWINX86 -DOS_CYGWINX86
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for Ada/C/ObjC but not for C++
gcc -fno-strict-aliasing -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -DID_OS="CYGWINX86" -DID_REL="2009.2" -DID_PATCH="240822" -DID_API="2010.2" -DID_Y="2010" -DID_M="04" -DID_D="02" -IC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -IC:\Pyt
hon\p4api\p4api-2010.2.295040-vs2010_static\/include/p4 -I/usr/include/python2.6 -c PythonSpecData.cpp -o build/temp.cygwin-1.7.9-i686-2.6/PythonSpecData.o -DOS_CYGWIN -DOS_CYGWIN -DOS_CYGWINX86 -DOS_CYGWINX86
cc1plus: warning: command line option "-Wstrict-prototypes" is valid for Ada/C/ObjC but not for C++
g++ -shared -Wl,--enable-auto-image-base build/temp.cygwin-1.7.9-i686-2.6/P4API.o build/temp.cygwin-1.7.9-i686-2.6/PythonClientAPI.o build/temp.cygwin-1.7.9-i686-2.6/PythonClientUser.o build/temp.cygwin-1.7.9-i686-2.6/SpecMgr.o build/temp.cygwin-1.7.
9-i686-2.6/P4Result.o build/temp.cygwin-1.7.9-i686-2.6/PythonMergeData.o build/temp.cygwin-1.7.9-i686-2.6/P4MapMaker.o build/temp.cygwin-1.7.9-i686-2.6/PythonSpecData.o -LC:\Python\p4api\p4api-2010.2.295040-vs2010_static\ -LC:\Python\p4api\p4api-2010
.2.295040-vs2010_static\/lib -L/usr/lib/python2.6/config -lclient -lrpc -lsupp -lpython2.6 -o build/lib.cygwin-1.7.9-i686-2.6/P4API.dll
/usr/lib/gcc/i686-pc-cygwin/4.3.4/../../../../i686-pc-cygwin/bin/ld: cannot find -lclient
/usr/lib/gcc/i686-pc-cygwin/4.3.4/../../../../i686-pc-cygwin/bin/ld: cannot find -lrpc
/usr/lib/gcc/i686-pc-cygwin/4.3.4/../../../../i686-pc-cygwin/bin/ld: cannot find -lsupp
collect2: ld returned 1 exit status
error: command 'g++' failed with exit status 1

To give a more concrete question, is ld looking in the wrong place or is something else going wrong that I'm not seeing? I'm out of ideas. Any help or guidance would be very much appreciated.

Answer 1

Here's a way I've used to turn lib files into shared libraies for use with gcc:

1. echo EXPORTS > NAME.def
2. nm NAME.lib | grep ' T _' | sed 's/.* T _//' >> NAME.def
3. dlltool --input-def NAME.def --dllname NAME --output-lib libNAME.a

Further notes on using Cygwin (but I use gcc 3 on an older 32-bit system, so YMMV) :

Install the gcc-mingw package (headers and libs for mingw for gcc and g++ 3) or one of the newer packages that use mingw-w64 for gcc 4.5. Also, compile with the option -mno-cygwin to keep from linking Cygwin into the executable/library. For Python extensions you can permanently configure distutils to use mingw by adding a distutils.cfg file to the Lib\distutils folder:

[build]
compiler = mingw32   #or mingw64

[build_ext]
compiler = mingw32   #or mingw64

I add C:\cygwin\bin to the Windows path (at the end to minimize interference) and compile from within Windows cmd. However, I have to replace the Cygwin symlinks with the actual executables (i.e., gcc3.exe -> gcc.exe, g++3.exe -> g++.exe) since Windows cmd doesn't understand the symlinks. It hasn't given me a problem yet compiling Python 3 extensions, Cython (even on-demand compiling with pyximport), swig, and embedding Python.

Answer 2

This might help in generating .a from .lib.