SCons to make a shared library (.so) with a static libarary (.a)

Question

I'm trying to get SCons to make a shared library. One of the items going into the .so is a .a static lib.

I have a line like: env_2.SharedLibrary('libstuff.so', Split("""stuff.cxx mylib/libMine.a""")

And upon running get an error: scons: * Source file: mylib/libMine.a is static and is not compatible with shared target: libstuff.so

However, I know that a shared library can be made from the .a via command like.

g++ -m32 -shared -o libstuff.so stuff.o mylib/libMine.a

Any ideas on getting this to work are doing the run around the issue would be greatly appreciated.

-jk

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Related question is how do I get scons to put an additional string "-shared" on the LINK command line for the Program() call. If I could do this, I think it would meet my needs.

Answer 1

This problem is not specific to scons. To build a shared library, you'll need objects that are compiled with position independent code (-fPIC). Your best bet is to make the shared library out of the source files compiled with the right options.

In SCons, you can define a list of targets that's used to build both libMine.a and libShared.so.

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Update: for your second question, the SharedLibrary builder might do what you need:

SharedLibrary('foo', ['f1.c', 'f2.c', 'f3.c'])

If not, LINKFLAGS sets the flags passed to a link command.

Answer 2

env_2.SharedLibrary('libstuff.so', Split("""stuff.cxx"""), LIBS='libMine.a', LIBPATH='mylib')

This should work.

Answer 3

I've the same problem under cygwin. I passed '-fPIC' options to gcc when building the objects and got the following warning:

warning: -fPIC ignored for target (all code is position independent)

I also passed '-shared' to the link command. And I finally got the error

"*.lib is static and is not compatible with shared target: myso.dll"

It seems scons doesn't allow to create so directly from obj or lib files, and one can either create the so from a list of sources files (using SharedLibrary()) or source file + 'LIBS' option like dummytaurus says. I'm curious about that.