The path to the binary directory currently being processed.

This is the full path to the build directory that is currently being processed by cmake. Each directory added by add_subdirectory() will create a binary directory in the build tree, and as it is being processed this variable will be set. For in-source builds this is the current source directory being processed.

When run in cmake -P script mode, CMake sets the variables CMAKE_BINARY_DIR, CMAKE_SOURCE_DIR, CMAKE_CURRENT_BINARY_DIR and CMAKE_CURRENT_SOURCE_DIR to the current working directory.