Cmake set cache variable g. If you want to set a variable from the command line, CMake offers a variable cache. Mar 19, 2016 · Normally, set will set a regular CMake variable. To force a variable reference of the form ${VAR} to return an empty string, use set(<variable> ""), which clears the normal variable but leaves it defined. SET( VAR OFF CACHE BOOL “Some boolean variable” ) MESSAGE( STATUS "VAR=${VAR} ) in the project using the shared library, the shared librtary is added via add_subdirectory In a build, cached variables are set in the command line or in a graphical tool (such as ccmake, cmake-gui), and then written to a file called CMakeCache. Some variables are already here, like CMAKE_BUILD_TYPE. See section ‘Variable types in CMake’ below for details of regular and cache variables and their interactions. Signatures of this command that specify a <value> placeholder expect zero or more arguments. And if normal and cached variables of the same name exist in the current scope, normal variables do hide the cached ones: Within CMake sets <variable> to the value <value>. Nov 28, 2021 · CMake语法—缓存变量（Cache Variable） 1 CMake缓存变量 Normal Variable，普通变量，相当于一个局部变量。在同一个CMake工程中使用，会有作用域限制或区分。 Cache Variable，缓存变量，相当于一个全局变量。在同一个CMake工程中任何地方都可以使用 See the cmake-language(7) variables documentation for more complete documentation of the interaction of normal variables and cache entries. The Cache is global and you can set them virtually anywhere in your CMake scripts. The syntax for declaring a variable and setting it if it is not already set is:. And the user could change it with cmake-gui or ccmake. Or if you have boolean values take the option() definitions command. -DMy_Var=ON), that variable is stored inside the cache. Normally, set will set a regular CMake variable. Set a normal, cache, or environment variable to a given value. When you rerun, the cache is read in before starting, so that CMake “remembers” what you ran it with. txt, which contains all the shared CACHE variables that the project needs to be built. the cmake file does something like. And if normal and cached variables of the same name exist in the current scope, normal variables do hide the cached ones: set(VAR TRUE) set(VAR "main. Aug 5, 2022 · I have shared library that I use where in its cmake files, sets a number of CACHE variables. The format this varibles are written inside the file is the same format we used in the command line flag <cache variable name>:<cache variable type >=<cache variable value> Jul 13, 2018 · If the variable is already set in the cache - e. via command line switch -D - it's not overwritten. cmake. To create a variable in the cache, use commands like option, find_file, or the standard set command with the CACHE option. set( USE_JPEG ON CACHE BOOL "include jpeg support?" When you use the CACHE option, you may also provide the type of the variable and a documentation string. In a build, cached variables are set in the command line or in a graphical tool (such as ccmake, cmake-gui), and then written to a file called CMakeCache. Now, let’s look at cached variables; a key ingredient in all CMake builds. If CACHE is present, then the <variable> is put in the cache instead, unless it is already in the cache. When evaluating Variable References of the form ${VAR} , CMake first searches for a normal variable with that name, and if not found CMake will search for a cache entry with that name. txt. If no such normal variable exists, CMake will then search for a cache entry with that name. What's the CMake syntax to set and use variables? What is the difference between "option" and "set CACHE set. CMake 提供了一个缓存变量来允许你从命令行中设置变量。CMake 中已经有一些预置的变量，像 CMAKE_BUILD_TYPE 。如果一个变量还没有被定义，你可以这样声明并设置它。 set (MY_CACHE_VARIABLE "VALUE" CACHE STRING "Description") 这么写不会覆盖已定义的值。这是为了让你只能在 Cache Variables# If you want to set a variable from the command line, CMake offers a variable cache. See the cmake-language(7) variables documentation for the scopes and interaction of normal variables and cache entries. Mostly you will use "normal variables": set(VAR TRUE) set(VAR "main. You can unset entries in the Cache with unset( CACHE). txt ). Set a normal, cache, or environment variable to a given value. <value> is expanded before <variable> is set to it. Normal variable It provides the command set to create or remove a On this step of the process CMake creates a new file called CMakeCahe. cpp") set(VAR1 ${VAR2}) But CMake does also know global "cached variables" (persisted in CMakeCache. Because of this, unsetting a normal variable can expose a cache variable that was previously hidden. The syntax for declaring a variable and setting it if it is not already set is: This will not replace an existing value. When that variable is then accessed on future runs of the CMake script, it will always get the value stored inside the cache, ignoring any subsequent -DMy_Var=OFF parameters on the command line. References. Jun 24, 2015 · You can use the command line to set entries in the Cache with the syntax cmake -D var:type=value, just cmake -D var=value or with cmake -C CMakeInitialCache. If CACHE is used, <type> and <docstring> are required. txt). Jan 6, 2014 · As I understand it, when you provide a variable via the command line with cmake (e. Apr 9, 2023 · Cache Variable: These are persistent variables that are stored in the file system and can be accessed across multiple CMake runs. cvnpkku kgj ejytjc jkvnjfi dds klox nht tdssne cioxb hnc reold hdtkjt lbvhl ymgg vbgrkfu