Libraries

add reimplementations of virtual functions (unless it it safe for older binaries to call the original implementation), because the compiler evaluates SuperClass::virtualFunction() calls at compile-time (not link-time).

add or remove virtual member functions, because this would change the size and layout of the vtbl of every subclass.

change the type of any data members or move any data members that can be accessed via inline member functions.

change the class hierarchy, except to add new leaves.

add or remove private data members, because this would change the size and layout of every subclass.

remove public or protected member functions unless they are inline.

make a public or protected member function inline.

change what an inline function does, unless the old version continues working.

change the access rights (i.e. public, protected or private) of a member function in a portable program, because some compilers mangle the access rights into the function name.

Each copy of the static library will have a different singleton

If code is not referenced directly it is stripped from the library

Globals or singletons can be a problem here

So application binary might not be "self-contained"

ar

ar -cvq libctest.a ctest1.o ctest2.o

gcc -shared -Wl,-soname,libctest.so.1 -o libctest.so.1.0 *.o

cc -o executable-name prog.c libctest.a

cc -o executable-name prog.c -L/path/to/library-directory -lctest

-L sets library search path, -l determines libraries to link against (no lib at the start or extension)

like static libraries

Or at run-time: