The configure step essentially "runs" the user-provided CMake code. After all of the code is executed, and all cache variable values have been computed, CMake has an in-memory representation of the project to be built. This will include all of the libraries, executables, custom commands, and all other information required to create the final build files for the selected generator. At this point, the CMakeCache.txt file is saved to disk for use in future runs of CMake. arguments to commands.