george anzinger wrote:
> 
> Georg Nikodym wrote:
> >
> > At the risk of sticking my foot in it, is there something wrong with the
> > ANSI C offsetof() macro, defined in <stddef.h>?
> >
> > --Georg
> No, and it could have been (and was) written prio to ANSI C defining
> it.  Something like:
> 
> #define offsetof(x, instruct) &((struct instruct *)0)->x
> 
> The issues that CPP resolves have to deal with the following sort of
> structure:
> 
> struct instruct {
>         struct foo * bar;
> #ifdef CONFIG_OPTION_DIDDLE
>         int diddle_flag;
>         int diddle_array[CONFIG_DIDDLE_SIZE];
> #endif
>         int x;
> }
> 
> Or for the simple need for a constant:
> 
> #define Const (CONFIG_DIDDLE_SIZE * sizeof(int))
> 
> Of course you could have any number of constant operators in the
> expression.  Note also, that the array in the structure above is defined
> by a CONFIG symbol.  This could also involve math, i.e.:
> 
> #define CONFIG_DIDDLE_SIZE CLOCK_RATE / HZ
> 
> and so on.  All in all, it best to let CPP do what it does best and
> scarf up the result:
> 
> #define GENERATE_CONSTANT(name,c) printf(#name " equ %d\n",c)
> 
> then:
> 
> GENERATE_CONSTANT(diddle_size,CONFIG_DIDDLE_SIZE);
> 
> In the code we did, we put all the GENERATE macros in a .h file.  The
> the code looked like:
> 
> #include.... all the headers needed....
> 
> #include <generate.h>
> 
> GENERATE....  all the generate macro calls...
> 
> } // all done (assumes that the "main(){" is in the generate.h file)
> 
> This whole mess was included as comments in the asm file.  The make rule
> then used a sed script to extract it, compile and run it to produce a
> new header file which the asm source included outside of the above
> stuff.
> 
> George

My script already handles that, everything is first passed through
CPP and the member offset are varied correctly according to any
compilation options.

I included the script and the results of two runs.

1. ./h2inc tst.h >tst.inc

2. ./h2inc --cflags="-DSHOW_HIDDEN -I./" >tst-hidden.inc

Regards