Installing headers the modern way

Code
1

I find myself doing this:

target_sources(mylib PUBLIC mypublic.h)
get_target_property(MYLIB_PUBLIC_HEADERS mylib INTERFACE_SOURCES)
set_target_properties(mylib PROPERTIES PUBLIC_HEADER "${MYLIB_PUBLIC_HEADERS}")
install(TARGETS mylib PUBLIC_HEADER DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/mylib")

Now, I’m well aware that CMake offers multiple ways to skin this cat. The above feels Mostly Modern; however, copying the INTERFACE_SOURCES property value to the PUBLIC_HEADER property feels awkward. (Why doesn’t target_sources..PUBLIC set this property?)

What is considered the Modern way to do something as straightforward as installing a library and its headers these days?

2

target_sources(PUBLIC) adds those files to the source list for any consuming target. It’s not quite the same thing. That said, I still use install(FILES) myself out of habit, so I don’t have much input to the question itself.

3

I understand it’s not quite the same thing; but, as a practical matter, if I’m providing an install target, is there a scenario in which I would not want INTERFACE_SOURCES to be installed?

4

Hmm. Probably not. I expect that would only lead to errors when the source file cannot be found upon usage of the target.

5

@Braden: Does the way you described work for you? Also when exporting / installing the targets? Which CMake Version are you using?
I am either getting

CMake Error in CMakeLists.txt:
 Target "mylib" INTERFACE_SOURCES property contains path:

   "D:/Some/path/include/mypbulic.h"

 which is prefixed in the source directory.

or

CMake Error in CMakeLists.txt:
  Target "mylib" INTERFACE_SOURCES property contains relative path:

    "include/mypbulic.h"

(First was minimum cmake 3.6, and some policy warning, second one minimum cmake 3.15)

So apparently it can be neither relative nor absolute? Do I need to work here with generator expressions as well? I am a bit confused.

(I am using CMake 3.20 here)

6

Please refer to my more recent posting, Installing headers the modern way, regurgitated and revisited.

The method described there does work. It is not pretty. I am using CMake 3.19.

1 Like
7

Thanks for the quick reply. I totally ended up doing what you described in your second approach. I also feels that this is way to verbose.
Most of the time I just install folders instead of the header files.