Fully Understand the concept of target_link_libraries

[two_Two]

I would like to fully understanding target_link_libraries .If I write

target_link_libraries( A B C )

In this case A(shared),B(static),C(shared) are libraries. I wonder:

1.What would the terminal command be in Ubuntu if I want to achieve same functionality?

2.What would system do for this statement, would system copy the content in B and C into A?

3.If I have to use A in other project, should I have to write target_link_libraries( A B C ) in that CMakeLists.txt once again even if something might happened when first time building A ?

[ben.boeckel (Ben Boeckel (Kitware))]

@two_Two

What would the terminal command be in Ubuntu if I want to achieve same functionality?

This really depends on what the link usage requirements B and C are. But assuming they are static libraries with no transitive dependencies or link option requirements, it just adds the full paths to the .a files to the link line.

@two_Two

What would system do for this statement, would system copy the content in B and C into A?

Generally, the sections which contain (transitively) used code would be copied over. Unused sections will not be copied (without other flags like --whole-archive).

@two_Two

If I have to use A in other project, should I have to write target_link_libraries( A B C ) in that CMakeLists.txt once again even if something might happened when first time building A ?

If the A target is exported through CMake as a target, the usage requirements will follow it around. Though in the simplified case I assumed here, nothing else would be necessary (CMake or no), but this doesn’t hold if B or C are more complicated.