Gabriel Dos Reis writes: > "Rafael Espíndola" <[EMAIL PROTECTED]> writes: > > | I am trying to build a table with offsets of global pointers from a > | given pointer: > | > | void *fs[] = {f1 - f1, f2 - f1}; > | > | where f1 and f2 are functions. > | > | GCC is able to figure out that (f1 - f1) is 0, but says "initializer > | element is not constant" when trying to compute (f2 - f1). > > because that is what the language standard says. > > In general, the difference between two global pointers is something > known only to the linker -- too late to evaluate as constant > expression.
And in any case it's not legal C: see Section 6.5.6 para 9. Andrew.