有条件地包括源文件

Question

在我的根CMakeLists.txt中

add_definition(-DMY_MACRO)

然后在一个子CMakeLists.txt我想做的事情

add_library(mylib, STATIC
    file1
#ifdef MY_MACRO
    file2
#endif
)

我试过类似的东西

IF( DEFINED MY_MACRO )
SET(FILE2 "file2")
ELSE( DEFINED MY_MACRO )
SET(FILE2 "")
END_IF( DEFINED MY_MACRO )

add_library(mylib static
    file1
    ${FILE2}
)

但没有快乐.

Answer 1

add_definitions添加预处理器定义,它不定义cmake变量.

我还没有测试过,但是如果你真的想要寻找预处理器定义,可能会更像这样:

set(mylib_SOURCES )
list(APPEND mylib_SOURCES file1)
get_directory_property(CURRENT_DEFINITIONS COMPILE_DEFINITIONS)
list(FIND CURRENT_DEFINITIONS "MY_MACRO" IN_CURRENT_DEFINITIONS)
if(NOT IN_CURRENT_DEFINITIONS EQUAL -1)
    list(APPEND mylib_SOURCES file2)
endif(NOT IN_CURRENT_DEFINITIONS EQUAL -1)
add_library(mylib static ${mylib_SOURCES})

(这里的定义是从父目录继承而来的)

在您的父母CMakeLists.txt中:

add_definitions(-DMY_MACRO) # should appear before going into subdirectories
add_subdirectory(foo)

基于变量的不同方法是:

• 父:

  option(WITH_FOO "with(out) foo option") # or set(WITH_FOO true/false)
  if(WITH_FOO)
      add_definitions(-DMY_MACRO)
  endif(WITH_FOO)
  add_subdirectory(foo)
  

• 子目录:

  set(mylib_SOURCES )
  list(APPEND mylib_SOURCES file1)
  if(WITH_FOO)
      list(APPEND mylib_SOURCES file2)
  endif(WITH_FOO)
  add_library(mylib static ${mylib_SOURCES})