My program layout is like this

typedef struct{
    double **a;
    double **b;

when I do this the values of result1 and result2 (ie... thier locations) are
0, even though (*new_struct).a != 0?

I've also tried
&(new_struct->psi[i][j])
but that also comes through as a 0.

how do I pass the address of an element of an array of double pointers from
within a structure pointer??

--

Hybrid Physicist/Mathematician/Computer Scientist
University of Waikato
New Zealand (PRO "New ZEE-Land")

(In)famous last words : "Demi-Lich?  That's only half a Lich isn't it??"

: typedef struct{
:     double **a;
:     double **b;
: } mystruct;

: void myfunction(double x,double y,double *result1,double *result2)
: {
:     stuff
: }

: void usemyfunction(double x,double y,mystruct *new_struct)
: {
:      allcate memory to (*new_struct).a and (*new_struct).b
:      stuff
:      myfunction(x,y,&((*new_struct).a[i][j]),&((*new_struct).b[i][j]));
:      stuff
: }

: My problem is the following;
: (i) after allocating some space to the pointers in mystruct
: (ii) how do I pass in the address of one of the elements of a field of that
: struct to myfunction(), like that above in usemyfunction()

: when I do this the values of result1 and result2 (ie... thier locations) are
: 0, even though (*new_struct).a != 0?

: I've also tried
: &(new_struct->psi[i][j])
: but that also comes through as a 0.

------->
           Have you allocated memory for (*new_struct).a[0], a[1], a[2]...
           ?
           Array of double pointers should take two phases.
              Phase I: allocate memory for pointers. (As in your program)
              Phase II: allocate memory for each pointer.  
                 ex:
                 for ( i = 0; i < 30; i ++ )
                   (*new_struct).a[i] = calloc ( 20, sizeof (double));

: how do I pass the address of an element of an array of double pointers from
: within a structure pointer??

  ------> As in your program.

     G o o d   L u c k !

     :)

                            Wiza  
                               (Wen-kae Tsao)
                               Computer Science & Information Engineering Dept.
                               National Taiwan University