Adding headers to a library in CMake

Question

I have quite a few libraries that look like this:

libs

     \lib1-- src
          \- include

      \lib2--src
           \- include

Where lib2 requires lib1. The way I have gotten by doing this is by doing something like this:

lib2/CMakeLists.txt: 
    include ../lib1/include
    target_link_libraries(lib2 lib1)

How can I include the lib1 header/include files in the lib2 library? I am currently trying to do this, but during compilation I get errors that lib2 can't find the lib1 header files.

libs/CMakeLists.txt:

file(GLOB lib1_src
    "lib1/src/*.cc"
 )

#header files
file (GLOB lib1_h
    "lib1/include/*.h"
 )


file(GLOB lib2_src
    "lib2/src/*.cc"
 )

#header files
file (GLOB lib2_h
    "lib2/include/*.h"
 )

add_library(lib1 ${lib1_src} ${lib1_h})
add_library(lib2 ${lib2_src} ${lib2_h})
target_link_libraries(lib2 lib1)

I can get it to work by adding include_directories(lib1/include) to the libs/CMakeLists.txt but I'm getting to the point where one library requires 3 others, which each requires 3 others, etc. and it's getting pretty tedious.

Are there any cases where libA/include will have a header that has the same name as libB/include but has differing contents? — JonnyRo, Jul 12 '13 at 00:39
Cool, then my suggested (and now accepted, thanks) solution should work just fine. — JonnyRo, Jul 15 '13 at 18:20

score 5 · Accepted Answer · answered Jul 12 '13 at 00:33

When you have a repetitive folder structure like this it is often handy to create a macro that automates this kind of stuff.

MACRO(ADD_SUBLIB libname)
  #Compute required sources
  file(GLOB sublib_sources "${libname}/src/*.cc")

  #Create library
  ADD_LIBRARY(${libname} SHARED ${sublib_sources})

  #add this library's header folder to the global include set
  INCLUDE_DIRECTORIES("${libname}/include")

ENDMACRO(ADD_SUBLIB)

#Call macro once per library
ADD_SUBLIB(lib1)
ADD_SUBLIB(lib2)
ADD_SUBLIB(lib3)

#Sample executable, who as a side effect of the macro calls will 
# be able to include.
ADD_EXECUTABLE(myprog main.cpp)

#Link any of the created libraries
TARGET_LINK_LIBRARIES(myprog lib1 lib2 lib3)

Adding headers to a library in CMake

1 Answers1