[CMake] How to create SOURCE_GROUP for include files

[Steve Johns]

> The source and header files will not magically be found in other 
> directories.  You have to tell CMake where to find them.  Try this in the 
> top-level CMakeLists.txt file:
>
> ADD_LIBRARY(mylib src/x.cpp incl/x.hpp)
> SOURCE_GROUP("Include Files" FILES incl/x.hpp)
>
> Basically source files have to be named with a relative path to the 
> location of the CMakeLists.txt file.  This may also work from 
> lib/CMakeLists.txt:
>
> ADD_LIBRARY(mylib ../src/x.cpp ../incl/x.hpp)
> SOURCE_GROUP("Include Files" FILES ../incl/x.hpp)
>

It works both ways, thank you very much!

__

As an aside, I would add that the "simple example" off of the documentation 
page starts one off in the habit of coding this:

ADD_LIBRARY(mylib ../src/x.cpp )
(which results in no "Header Files" group being created)


instead of this:

ADD_LIBRARY(mylib ../src/x.cpp ../incl/x.hpp)
(which results in a "Header Files" group being created for you )

One could read the example as implying that the .cpp dependence upon .hpp is 
implied and "automagical".

What actually seems to be "automagical" is the creation of a "Header Files" 
group when header files are explicitly listed as dependencies.

I grant that the example is not referring to header files because it is "so 
simple" that header files are not even present at all.  However, I think it 
might actually save people some run-around (taking myself as a case in 
point!) if the example were just slightly more complex to illustrate the 
"useful and proper" inclusion of header files in dependency lists (my $.02 
worth).

Thanks again for the assistance!  :^)