在CMake中，CHECK_INCLUDE_FILE_CXX如何工作？

Question

下面的代碼打印什麼

CHECK_INCLUDE_FILE_CXX(glog/logging.h GLOG_INCLUDE) 
IF(GLOG_INCLUDE) 
    MESSAGE("YY") 
ENDIF(GLOG_INCLUDE) 

但我有以下環境變量設置：

export CPLUS_INCLUDE_PATH=/usr/local/include 

而且， 「LS /usr/local/include/glog/logging.h」 返回文件。

我嘗試使用

include_directories("/usr/local/include") 

但GLOG_INCLUDE之後剩下的不確定（logging.h仍然沒有找到。）

Answer 1

看一看的CheckIncludeFileCXX.cmake。它應該在你的cmake安裝目錄下（我在/usr/share/cmake-2.8/Modules中有它）。

該文件指出：

# The following variables may be set before calling this macro to 
# modify the way the check is run: 
# 
# CMAKE_REQUIRED_FLAGS = string of compile command line flags 
# CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar) 
# CMAKE_REQUIRED_INCLUDES = list of include directories 
# 

所以，你可以嘗試caling命令之前設置該變量，就像這樣：

set (CMAKE_REQUIRED_INCLUDES "/usr/local/include") 
CHECK_INCLUDE_FILE_CXX(glog/logging.h GLOG_INCLUDE) 
IF(GLOG_INCLUDE) 
    MESSAGE("YY") 
ENDIF(GLOG_INCLUDE)