Const vs Static Const
c, constants, memory, object, static
Solution
It depends on your system, and on how you use the variable. For `static` variables:
Case 1: You never use the variable, and the compiler silently discards it. This cannot happen with `extern` variables.
Case 2: You use the variable, but you never take its address. The compiler converts use of the variable to immediate operands, just as if it were a `#define` or `enum`. The compiler can still convert `extern` static to immediate operands, but it must still find an address for it anyway.
Case 3: You use the variable and take its address, the compiler is forced to find a place to put it in the object code, exactly as if it were `extern`.
As for "data" versus "program" memory, well, that is very specific to the system you are using. On my Linux x64/ELF system, it will probably get put in the `.rodata` section, which goes in the same segment as code (`.text`), but a different segment from read-write data sections (`.bss`, `.data`). My system appears not to create a separate segment for read-only non-executable data.
Addendum: Note that the behavior is different in C++. In C++, a `const` variable has internal linkage by default, so `static const` is redundant and `extern const` is necessary to get a constant with external linkage.
Problem
How does the compiler (e.g. GCC) allocates `const` and `static const` variable, as in, where would it reside? In data memory or program memory?