[CMake] How to force cmake to run on a different source directory?

Hi, The following directory has 'cmake ../src1' run before. I get the following error when I run the following command. One way to solve the problem is to run "rm -rf *", but I'm wondering if there is a way to force cmake to run even when the source directory changes. I don't see such a command line option in the manual. Thanks! ~/linux/test/cmake/lang/command/message/build$ cmake ../src/ CMake Error: The source "/Users/pengy/linux/test/cmake/lang/command/message/src/CMakeLists.txt" does not match the source "/Users/pengy/linux/test/cmake/lang/command/message/src1/CMakeLists.txt" used to generate cache. Re-run cmake with a different source directory. -- Regards, Peng