CMake 添加子目录错误 : "When specifying an out-of-tree source a binary directory must be explicitly specified"

Question

我的目录结构如下:

root
  libA
    CMakeLists.txt
    ClassA.cpp
  libB
    CMakeLists.txt
    ClassB.cpp
  sharedCode
    enums.h
    AbstractClass.h

CMake文件中如何包含sharedCode目录？这样 classA(在 libA 中)和 classB(在 libB 中)都可以使用 enums.h 和 AbstractClass.h？

在我尝试使用的 CMakeLists.txt 中:

add_subdirectory(../sharedCode)

但它给出了错误

  add_subdirectory not given a binary directory but the given source
  directory "/root/sharedCode" is not
  a subdirectory of "root/libA".  When
  specifying an out-of-tree source a binary directory must be explicitly
  specified.

Answer 1

如错误所述，当指定当前树之外的相对源目录时，您还必须提供第二个参数来指定将放置生成的二进制文件的目录。

Here's the documentation对于 add_subdirectory:

The binary_dir specifies the directory in which to place the output files. If it is a relative path it will be evaluated with respect to the current output directory, but it may also be an absolute path. If binary_dir is not specified, the value of source_dir, before expanding any relative path, will be used (the typical usage). The CMakeLists.txt file in the specified source directory will be processed immediately by CMake before processing in the current input file continues beyond this command.