On 12 Aug 98 at 20:47, Masaharu Goto wrote:
> Hi Masa,
> As you might remember we discussed this item already a long time ago
> (when I needed it to get random numbers according to a user defined
> function in which I needed to pass the pointer to that interpreted
> user function to a pre-compiled member function). The I suggested
> the idea of a ROOT/CINT facility of the sort of
>
> // The user function in the interpreted code
> float func(float x)
> {
> return (x*x-2*x+25);
> }
>
> // The main program
> void test()
> {
> Random q;
> float a=6;
> float b=9;
> int nbins=100;
> // Provide a random number in <a,b> according to function func //
> using nbins between a and b
> q.User(a,b,nbins,GetPointer(func));
> }
I would like to note the pointer alone is not sufficient to
make call any function. One has to define the formal arguments list
of that function within the q.User prototype too. This means
strictly say we need the family of the GetPointer methods (or special
"infinite" (template ?) class) for each combination of the possibly
arguments.
I mean
typedef ( *)(int) funcint1;
typedef ( *)(int,int) funcint2;
typedef ( *)(float) funcifloat1;
etc etc etc
funcint1 GetPointer(funct1);
funcint2 GetPointer(funct2);
funcfloat1 GetPointer(funfloat1);
etc etc etc
Therefore I would like to understand whether there is a good
solution on C++ level, then ask CINT to implement this.
(I'd like to call your attention on some platfroms one can make a
trick returning void * instead of real pointer-to-real-function and
then cast it to what he/she wants, but this trick is not general
one and does't work for some compiler/platform combinations ).
Anyway I would like to avoid any "trick" on the CINT level.
Valery
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Dr. Valeri Faine (Fine)
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