1CMAKE_GENERATOR_INSTANCE 2------------------------ 3 4.. versionadded:: 3.11 5 6Generator-specific instance specification provided by user. 7 8Some CMake generators support selection of an instance of the native build 9system when multiple instances are available. If the user specifies an 10instance (e.g. by setting this cache entry or via the 11:envvar:`CMAKE_GENERATOR_INSTANCE` environment variable), or after a default 12instance is chosen when a build tree is first configured, the value will be 13available in this variable. 14 15The value of this variable should never be modified by project code. 16A toolchain file specified by the :variable:`CMAKE_TOOLCHAIN_FILE` 17variable may initialize ``CMAKE_GENERATOR_INSTANCE`` as a cache entry. 18Once a given build tree has been initialized with a particular value 19for this variable, changing the value has undefined behavior. 20 21Instance specification is supported only on specific generators: 22 23* For the :generator:`Visual Studio 15 2017` generator (and above) 24 this specifies the absolute path to the VS installation directory 25 of the selected VS instance. 26 27See native build system documentation for allowed instance values. 28