//"option"用来定义宏,"ON"表示打开,"OFF"表示关闭
option (USE_MYMATH "Use tutorial provided math implementation" ON)
4 configure_file
//configure_file: 将一份文件拷贝到另一个位置并修改它的内容
# configure_file(<input> <output> [COPYONLY] [ESCAPE_QUOTES] [@ONLY])
# configure a header file to pass some of the CMake settings to the source code
configure_file (
"${PROJECT_SOURCE_DIR}/TutorialConfig.h.in"
"${PROJECT_BINARY_