Why can't I allocate an array of function pointers into FLASH?

[wre]

Hi, using CodWarrior 3.1 for HC(S)08, I am trying to get an array of function pointers allocated into FLASH (.rodata).  Instead they are allocated into RAM (.data) and initialization code loads the array.

Here is what I am doing:

const void (*sapfnIPHandlers [])(void) =

{

  func1,

  func2,

  func3,

  ...

  funcn

}

void func1 (void)

{

  ...

}

etc.

I have tried the -Cc compiler option with no change in the output.

This code is simply a way of parsing some commands to get to the right function.  What am I doing wrong (or what is the compiler doing wrong)?

Thanks

[CompilerGuru]

The reason why the array ends up in RAM is a common error in C programming.
For pointers (including function pointers), qualifiers have to be after the *, hence this array:
>const void (*sapfnIPHandlers [2])(void);
if not constant. You can assign to it, try

>void test(void) { sapfnIPHandlers[0]= fun; }

The correct version is:
>void (*const sapfnIPHandlers [2])(void)= {fun0, fun1};

Well this works, but it is a bit hard to read in my point of view.
So for functions, I would use a typedef instead:

>typedef void (*FunctionType)(void);
>const FunctionType sapfnIPHandlers[2]= {fun0, fun1};

Bye
Daniel

[wre]

Many thanks for both responses.  The first one got me going without using RAM and the second simplifies things...although I will have to study it a bit more to see what it is actually doing...

typedef void (*FunctionType)(void);

OK, I see that it matches an example from K&R such that it is creating the type FunctionType which is a pointer to a function with no arguments and returns nothing.

Thanks

Message Edited by wre on 04-18-200611:54 AM

[tequila]

Function pointers are normally stored in RAM, here is a workaround:

const unsigned int pFunction[]={(unsigned int)&SafePoint,(unsigned int)&BlackButton};

and you call it this way:

 ((void (*)(void))pFunction[0])();

Cheers