David Abrahams wrote:
Vladimir Prus wrote:
dariomt@gmail.com wrote:
Hi all,
I'm using header-only boost libs in two static libraries that will be linked into an executable.
No boost components are used in the interfaces of those libs, boost is only used in the implementation inside the libraries.
Is it possible to mix versions of boost in those two static libraries? Will the linker complain, or will it just get confused and mess up the executable?
In general, this is highly risky business. On GCC, each static library will contain a copy of every template function used by a static library. If the linker finds that the same function is used in both static libraries, it will put only one copy in the output executable, and if the definitions of those functions differ, you're in trouble. See the attached example, which, then run, produces:
a.cpp:say a.cpp:say
Which is clearly wrong. This *might* work with shared libraries, but you need to consult your toolchain documentation.
For the past few years we've had a GCC option that allows you to expose from dynamic libs only those names you specify, sort of like declspec on Windows. I don't remember the name of the flag, though.
-fvisibility, I believe. I actually though there's a way to cause a shared library to prefer its own symbols -- but apparently it's not possible, at least with gcc, in any easy way. - Volodya