添加cmake查找单库

cpp/cmake.txt

@@ -283,3 +283,30 @@ Test project /Users/Farmer/gitee/cmake-template/cmake-build
 在CMake 3.20往后的版本中，ctest可以使用--test-dir指定测试执行目录。
 
 至此，一个较为完备的CMakeLists.txt就开发完成了。
+
+如果是没有cmake的库，可以这样写：
+include_directories(${OPENCV4_ROOT}/include)
+set(LIBDIR ${OPENCV4_ROOT}/x64/vc15/lib)
+find_library(OPENCV4LIB 
+    opencv_core481 
+    opencv_imgproc481 
+    opencv_highgui481 
+    ${OPENCV4_ROOT}/x64/vc15/lib
+)
+MESSAGE(STATUS "OPENCV4LIB: ${OPENCV4LIB}")
+add_executable(useopencv4 main.cpp)
+target_link_libraries(useopencv4 PRIVATE 
+    debug 
+    ${LIBDIR}/opencv_core481d.lib 
+    ${LIBDIR}/opencv_imgcodecs481d.lib 
+    ${LIBDIR}/opencv_highgui481d.lib 
+)
+target_link_libraries(useopencv4 PRIVATE 
+    optimized 
+    ${LIBDIR}/opencv_core481.lib 
+    ${LIBDIR}/opencv_imgcodecs481.lib 
+    ${LIBDIR}/opencv_highgui481.lib 
+)
+其中可以使用find_library
+find_library(SDL2MAIN SDL2main ${SDL2_DIR}/lib)
+不过貌似只能单个找寻。