C / C++ / MFC

storagepointer = new CRichEditCtrl;

The control calls the callback function repeatedly, transferring a portion of the data with each call.

Matrix.add(m1,m2);
Matrix.div(m3,m4);

using Matrix {

   add(m1,m2);
   div(m3.m4);
}

namespace Matrix {
   
    void add(matrix a, matrix b){
       ...
       
    }

    void div(matrix a, matrix b){
       ...
       
    }

    void mul(matrix a, matrix b){
       ...
       
    }
    .
    .
    .



}

int  CALLBACK EditWordBreakProc(LPTSTR lpszEditText, int ichCurrent, int    cchEditText, int code)
{
	char FAR* lpCurrentChar;
	int  nIndex;
	int  nLastAction;

	switch (code)
	{

	case WB_ISDELIMITER:

		

		if (lpszEditText[ichCurrent] == 0x0a0d)
			return TRUE;
		else
			return FALSE;

		break;
	}
}

	fptrx = &EditWordBreakProc;
	storagepointer->SendMessage(EM_SETWORDBREAKPROC, 0,(LPARAM) fptrx);
long numstream = storagepointer->StreamIn(SF_TEXT,STORAGESTREAM);

funcptrx fptrx;

int CALLBACK EditWordBreakProc(LPTSTR lpszEditText, int ichCurrent, int    cchEditText, int code);

typedef int (CALLBACK *funcptrx) (LPTSTR, int, int, int);

struct MyStruct
{
  int small_or_big;
  int variable_part[0]; //or int variable_part[] if you want to conform to C90
};

struct MyStruct *ptr;
if (ptr->small_or_big == BIG_STRUCT)
{
  ptr->variable_part[999] = some_value; //we know that variable part size is 1000
  //...
}

//...
ptr_small = malloc(sizeof(MyStruct) + SIZE_OF_SMALL_PART);
ptr_small->big_or_small = SMALL_STRUCT;

ptr_big = malloc (sizeof(MyStruct) + SIZE_OF_BIG_PART);
ptr_big->big_or_small = BIG_STRUCT;