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Is is possible to use list instead of variables in case of cache variables?
Here how I use cache variables
set(VAR "Value" CACHE INTERNAL "My Var")
set(VAR "${VAR} Value2" CACHE INTERNAL "My Var")
897
The CMake cache may be thought of as a configuration file. The first time CMake is run on a project, it produces a CMakeCache. txt file in the top directory of the build tree. CMake uses this file to store a set of global cache variables, whose values persist across multiple runs within a project build tree.
CMake caches variables and settings in the CMakeCache. txt file. When you load a project for the first time, this file is generated in the build directory (cmake-build-debug or cmake-build-release by default) according to the contents of CMakeLists. txt.
Cache variables (unless set with INTERNAL) are mostly intended for configuration settings where the first CMake run determines a suitable default value, which the user can then override, by editing the cache with tools such as ccmake or cmake-gui.
A list in cmake is a ; separated group of strings. To create a list the set command can be used. For example, set(var a b c d e) creates a list with a;b;c;d;e , and set(var "a b c d e") creates a string or a list with one item in it.
CMake lists are semi-colon separated, so you can set the list directly like this:
set(VAR Value;Value2 CACHE INTERNAL "My Var")
Having said that, even though lists are held as semi-colon separated items, they can be constructed using set with spaces between each item; e.g.
set(MyList Value Value2) # list is Value;Value2
So, if your values contain spaces, you need to wrap the list in quotation marks ":
set(VAR "Value 1;Value 2" CACHE INTERNAL "My Var") # list is Value 1;Value 2
The final point is that if you already have your list constructed, you don't need to wrap the list variable in quotation marks when caching it:
set(MyList "Value 1;Value 2") # list is Value 1;Value 2
set(VAR ${MyList} CACHE INTERNAL "My Var") # no quotes required
As I now understand it, you're asking if the list(APPEND...) command can be used to cache values directly.
The answer is no, but you were almost correct in your attempt. To get the desired effect, you'd need to use a semi-colon rather than space when caching the list:
set(VAR "${VAR};Value2" CACHE INTERNAL "My Var")
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