In C , the usage of static const and const can lead to semantic differences. Let's explore these differences specifically for both linkage and storage class contexts.
At file scope, both static const and const variables behave identically. They both default to internal linkage, and all global variables possess static lifetime. However, the static keyword may align with C's behavior, providing a potential reason for its usage in this context.
Within a function, const int x = 0; allows for computation from parameters, unlike static const int x = 0;. This signifies that the former doesn't necessarily require a compile-time constant as some other languages mandate.
Inside a class, the distinction is similar to that in functions. An instance const value can be computed in the ctor-initializer-list, while a static const is defined during startup initialization and remains unaltered. Note that the syntax for static members differs as declaration and initialization are separate.
It's crucial to remember that const in C implies read-only, not constant. If a pointer-to-const is involved, other program components may modify the value even while the variable remains constant. The initialization process for constant variables can still be intricate, but they cannot be altered post-initialization.
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