Cmake Set Variable

Set a normal cache or environment variable to a given value.

Cmake set variable. Normal variables and cache variables. Environment variables may differ from where cmake generated the make environment and when the the make files are put to use. Cmake uses many variables that are officially documented. It s a lot like the include directive in c c.

Placeholder expect zero or more arguments. A lot of variables used by cmake are set with the project and enable language calls. Signatures of this command that specify a value. Some of the information in environment variables is also available through cmake system introspection variables but you may find it more convenient to use the environment variable.

When we faced the same issue you have a toolkit which produces a script so set the compile environment we changed the toolkit in a way that it produces a toolchain file along with the script. It s typically used to define a common set of functions or macros in the calling script. Set my cache variable value cache string description this will not replace an existing value. These have default values or values that are based on your project environment.

If you want to set a variable from the command line cmake offers a variable cache. In fact defining your own custom variables makes your cmakelists txt file. The include command executes another cmake script in the same scope as the calling script. To see the available variables for an environment open the corresponding command prompt and type set.

Multiple arguments will be joined as a semicolon separated list to form the actual variable value to be set. Mostly you will use normal variables. Example set my variable the value is a string by default a local variable is only defined in the current directory and any subdirectories added through the add subdirectory command. Variable types in cmake in cmake there are two types of variables.

In which case the environment variable will be set. The only way to set a compiler and flags to do cross compilation reliably with cmake is with a toolchain file as done in the tutorial you have found. Some variables are already here like cmake build type. They are not persisted across cmake runs.

Normal variables are meant for the internal use of the script just like variables in most programming languages. So it could get important to set some variables before those commands are used. It uses the variable cmake module path as a search path. You are allowed to change the value of these variables in your cmakelists txt.

To extend the scope of a variable there are two possibilities. See the cmake language 7 variables documentation for the scopes and interaction of normal variables and cache entries. Cmake variables are defined at file scope.