Function vs. Macro in CMake

Question

The official document of CMake 2.8.12 says about macro

When it is invoked, the commands recorded in the macro are first modified by rep

Answer 1

Another notable difference between function() and macro() is the behavior of return().

From the cmake documentation of return():

Note that a macro, unlike a function, is expanded in place and therefore cannot handle return().

So because it is expanded in place, in a macro() it returns from the caller. While in a function it just exits the function()

Example:

macro(my_macro)
    return()
endmacro()

function(my_function)
    return()
endfunction()

my_function()
message(hello) # is printed
my_macro()
message(hi) # is not printed