CMake : How to get the name of all subdirectories of a directory?

I have two questions relative to CMake

1. Assume that we have a variable ${MY_CURRENT_DIR} that contains the path of a directory that contains several subdirectories : mydir1, mydir2 and mydir3. I want to detect these subdirectories and put their names into ${SUBDIRS} (not the complete path of these directories, only their name). How to do that automatically ?

2. Assume that ${SUBDIRS} contains "mydir1 mydir2 mydir3". How to replace

   ADD_SUBDIRECTORY(mydir1)
   ADD_SUBDIRECTORY(mydir2)
   ADD_SUBDIRECTORY(mydir3)
   

by a loop over ${SUBDIRS}?

Solution 1:

1. Use this macro:

   MACRO(SUBDIRLIST result curdir)
     FILE(GLOB children RELATIVE ${curdir} ${curdir}/*)
     SET(dirlist "")
     FOREACH(child ${children})
       IF(IS_DIRECTORY ${curdir}/${child})
         LIST(APPEND dirlist ${child})
       ENDIF()
     ENDFOREACH()
     SET(${result} ${dirlist})
   ENDMACRO()
   

   Example:

   SUBDIRLIST(SUBDIRS ${MY_CURRENT_DIR})
   

2. Use foreach:

   FOREACH(subdir ${SUBDIRS})
     ADD_SUBDIRECTORY(${subdir})
   ENDFOREACH()
   

Solution 2:

In regard to answer above: Use this macro:

MACRO(SUBDIRLIST result curdir)
  FILE(GLOB children RELATIVE ${curdir} ${curdir}/*)
  SET(dirlist "")
  FOREACH(child ${children})
    IF(IS_DIRECTORY ${curdir}/${child})
      LIST(APPEND dirlist ${child})
    ENDIF()
  ENDFOREACH()
  SET(${result} ${dirlist})
ENDMACRO()

Example:

SUBDIRLIST(SUBDIRS ${MY_CURRENT_DIR})

I had trouble with this FILE(GLOB command. (I'm on cmake 3.17.3) Otherwise the macro works great. I was getting FILE GLOB errors, something like "FILE GLOB requires a glob expression after the directory." (Maybe it didn't like RELATIVE and/or just using the curdir as the fourth paramter.)

I had to use:

FILE(GLOB children ${curdir}/*)

(taking out RELATIVE and the first ${curdir} (Please note my cmake version above, that could've been my issue (I'm unfamiliar with glob so far.).)