struct

[newdep]

Hello All,



Has anyone a tip on how i can call a C struct created under newlisp

from within a C function?



Norman.

[newdep]

Hello Lutz,



I spitted trought the manual and broke my head on how to create a

C Struct under newlisp (even tried using 'dump with pointer redirection)

but its not working ;-)



I looped into some other Lisp distributions and there are some using it..



Have you thought about extenting newlisp with creation of a C struct which

can be called from within a 'imported C function?



i.e.



(set-struct 'testing

  (set 'one 2)

  (set 'two "world"))



>(get-string testing'two)

"world"



>testing

12347653  (pointer)



>(cfunction 1 2 3 testing)







Norman

[newdep]

Mmm perhpas a nelwisp struct function besides the context function?



Or even a possebility for a context to be used as a struct inside C functions?



Im just thinking out loud....

[Lutz]

This is what you can do:



Lets say you have the following 'C' struct



typedef struct

   {

    int ivalue;

    double fvalue;

    }  MYSTRUCT;



and a 'C' function doing something to that structure snd returning a string pointer:



char * foo(MYSTYRUCT * data)

{

char * result;



data->ivalue = 2 * data->ivalue;

data->fvalue = 10 + data->fvalue;



result = "OK";



return(result);

}



In newLISP you can constuct this structure:



(set 'mystruct (pack "ld lf" 123 4.56))



(import "mylib" "foo")



(get-string (foo mystruct)) => "OK"



(unpack mystruct "ld lf") => (246 14.56)





Lutz

[newdep]

;-)



Thanks...