Returning Pointer To Pointer From Function 
Author Message
 Returning Pointer To Pointer From Function

: I would appreciate some advice on how to correctly write a function
: prototype, and how to use the variable that was passed.  I'll explain
: what the situation is.  Before I gave up on this, I was getting syntax
: errors no matter what I tried.

: At the top of the program, I set up a define
: "define TYPE_16BIT_UNSIGNED unsigned small".  In a function, I used
: malloc to get a pointer to an array of TYPE_16BIT_UNSIGNED.  This was a one
: dimensional array which stored a two dimensional image, one row after the
: other.  In the function, I used malloc to allocate memory for an array of
: pointers to variables of type TYPE_16BIT_UNSIGNED.  Each element in the
: pointer array was then initialized to point to the first element of a row
: in the first array.  What I couldn't figure out was how to set up the
: function prototype so that I could return the pointer to the image array,
: and the pointer to the array of pointers.

: If the variables were local to the function, I think that the definitions
: would be similar to:

: TYPE_16BIT_UNSIGNED *image_ptr;  /* pointer to image array */
: TYPE_16BIT_UNSIGNED **image_row_ptr;  /* pointer to array of row pointers */

: After initialization, I could access elements in the image array by writing:

: image_row_ptr[i][j] = 0;

: But, the compiler didn't seem to like me defining the image_row_ptr in
: the function prototype as:

: TYPE_16BIT_UNSIGNED ***image_row_ptr

: Does anyone have a suggestion?  Please send it to me by e-mail if you
: do.  Thanks.

: --

: ============================================================================

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: ============================================================================

--
***************begin r.s. response******************

        try using a
                typedef
        rather than
                #define
        for this ...

***************end r.s. response********************
Ralph Silverman



Fri, 01 Oct 1999 03:00:00 GMT  
 
 [ 1 post ] 

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