Do statically linked libraries require linking with their dependencies?

Question

I'm building an executable that depends on a static library A which in turn depends on a static library B. When I build my application, do I need to also link against B in my build script?

To be more specific, do I need to do -la -lb , or, just linking with A via -la is enough?

Answer 1

You might or might not have to link with both libraries, depending on how A was built.

If A contains a linker comment record instructing the linker to also look in library B for symbols (typically included in one of the object files contained within A), you don't need to include B when you link. If A does not contain that comment record, you must include it yourself.

Answer 2

If both A and B are static, then you have to link both, in order of A then B ( -la -lb ). See this reply for an explanation of the order.

A statically linked program includes the libraries its linked against inside of the executable.

Imagine your program calls foo() inside of A, and somewhere inside of A, bar() gets called. So if A becomes part of your program, you then have an undefined call to bar() in your program, which is why you need to link against B as well.

The exception to this is when a special Visual Studio pragma is used ( #pragma comment(lib, libname) ) as mentioned by @1201ProgramAlarm.

Answer 3

A static library is completely included in the using program during compile time, so that it won't need any additional file to run the program.

If library A was already build with the static library B, A has B already and won't need it again.