10.4 Variables in Program Memory

To have objects placed into program memory, which is Flash memory on most target devices, they should be qualified const and additionally use the space(prog) attribute, for example:

const int __attribute__((space(prog))) const_symbol;

This combination places the object const_symbol into a .text section rather than a .rodata section. You still need to use the space(prog) attribute even if you are also using a section() attribute. Failure to use the const specifier with the space(prog) attribute will result in a compilation error: space("prog") object 'symbol' should be const qualified.