Linking two libraries built with c++_static

Question

In the following webpage,

https://developer.android.com/ndk/guides/cpp-support

it states that having two libraries (libA.so, libB.so) compiled with c++_static breaks the one-definition rule, in which multiple symbols will be defined for c++ functions in the different libraries. This case is then undefined behaviour, where multiple bugs could occur.

However, I don't know if this also happens for the following scenario:

• I compile libA.a linked agsint c++_static
• I then compile libB.so and link against c++_static and libA.a

In such case, the problem would not occur, and it would be safe to link the shared library against the static library, am I correct? Or are the symbols from libc++ embedded in libA.a?

Answer 1

It is safe. In fact, neither libA.a nor libB.a will be linked against libc++. Static libraries are not linked against their dependencies - this is done when linking executables/shared objects which use those libraries.

The only code from libc++ that will end up in those two static libs will be (inlined) code from headers. That's not a problem.