> On Jun 22, 2018, at 3:19 AM, Marc Santhoff <[email protected]> wrote:
> <Pascal>
> function HOFFSETP(rectypevar: pointer; fieldvar: pointer): longint; inline;
> begin
> HOFFSETP := longint(fieldvar - rectypevar);
> end;
>
> H5Tinsert(s2_tid, 'c_name', HOFFSETP(@s2[0], @s2[0].c), H5T_NATIVE_DOUBLE);
> H5Tinsert(s2_tid, 'a_name', HOFFSETP(@s2[0], @s2[0].a), H5T_NATIVE_INT);
> </Pascal>
So there was a solution but I can see why the C macro version was easier to
look at it. Was that not a good reason to use a macro? I like how the macro
cleaned that up. Sven’s suggested answer of "@s1_t(nil^).a” is even more
obscure imo.
If you guys don’t mind I may try to remember and collect the uses of macros
I’ve wanted at random times through out the year and see if there is indeed not
practical or good use for them in modern Pascal.
Here’s a macro I like from C. It captures the assert expression and prints it
back out into the console (it would halt the program also). Can this be done in
Pascal? In C they return the file name and line number also which is really
nice.
{$define assert(x):=if not (x) then writeln('assert: x')}
var
i: integer = 100;
begin
assert(i = 101); // assert: i=101
end.
Regards,
Ryan Joseph
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