Jumptable creation _ Embedded development

[ATFred]

Hello all,

I have a little problem with what seems to be a standard gcc error.
I am developping a little application for 8bit microcontroller and I need to create a jumptable, because access is a key to save space.

Typically, I have:
>>>>>>>
void func1()
{...}

void func2()
{...}

unsigned short globalVar = &func2() - &func1();

int main()
{return globalVar;}
<<<<<<<

I get the error:
"[...] error: initializer element is not computable at load time"

Of course, it relates to the initialisation of "globalVar" parameter. What I don't understand is, that func1 and func2 should have a fixed address and location. So, why does the gcc compiler does not want to initialize my global variable?

(of course, this is only an example, at the end, I should have a structure/array with all function adress, but the problem is still initializing the global parameter with function's address).

Does anyone know a tips to help solve this issue?

Thank you in advance, gentlemans !

Fred

[weaknessforcats]

You cannot have code executing outside a function.

Define your global variable and do the calculation &func2() - &func1() inside main() and assign the result to your variable.

If you were using C++, you could put this in the class constrcutor which would be called when the global variable is created.

But I'm guessing you are using C because your refer to gcc rather then g++.