abigagli / linux-shlib-link-samples Goto Github PK

These are a few examples illustrating how to properly link against a Linux shared library having secondary dependencies.

Please refer to this article for a better understanding of the samples.

You can build the samples either using:

• manually using the provided Makefile,
• with CMake using the provided CMakeLists.txt
• with Autotools using the provided configure.ac/Makefile.am

##Manual build

The Makefile illustrates the way things should be done as described in the aforementioned post.

To build the samples:

make VERBOSE=1

##CMake build

mkdir cmake-build
cd cmake-build
cmake ..
make VERBOSE=1

The key points with the CMake build are that:

• you have to tell CMake not to insert an rpath whenever a shared object is linked against,
• you must specify that the dependency between bar and foo is private to avoid it being exported to app

##Autotools/libtool build

autoreconf -fi
mkdir autotools-build
cd autotools-build
../configure
make VERBOSE=1

The key points with the autotools/libtool build are that:

• for each library, both a static and a shared version are generated,
• when you force a static link, it applies to all libraries (you cannot tell libtool to link statically with libbar and dynamically with libfoo)
• libtool inserts rpath in all objects linked to a shared library unless it is in the dynamic linker search path. This behaviour is usually not compatible with component packaging and patched by every single distribution (including cross environments).