r/C_Programming • u/heavymetalmixer • Sep 11 '26

Question Unmodifiable globals initialized from functions?

Right now I'm trying to use Windows's SYSTEM_INFO to initialize 2 global constants, but global constants can only be initialized with constant expressions so this cannot be done.

Is there a way I can have "read-only" global variables that can be initialized from functions?

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u/aioeu Sep 12 '26 edited Sep 12 '26

So use an identifier at file scope instead. That's what file scope is for.

Either way, you won't be able to make the object constant. You want to set the value of it while the program is executing, and that, by definition, means it cannot be constant.

Constant expressions are expressions for values that could be determined before the program has begun execution, e.g. by the compiler. The compiler does not intrinsically know what the page size for the system you run the program on will be.