void* problem

[Mithoric]

I'm building a data grid control.

It's struct which is I set in SetWindowLong is the MITH32GRIDSTRUCT struct.

typedef struct{
   LPSTR lpText,lpValue;
   int id,iIndex,iNumObjects,iType,iValue;
   bool bState,bValue;
   void *objects;
   RECT rc;
 }GRIDOBJECT;
 
 typedef struct{
   GRIDOBJECT*stems;
   int iNumStems;
   bool bInit,bSet;
   HICON *icons;
 }MITH32GRIDSTRUCT,*lpMITH32GRIDSTRUCT;

Anyway, as you can see the grid has an array of GRIDOBJECT (stems)..

I needed GRIDOBJECT to have an array of GRIDOBJECT, I could have made an identical struct but I thought I could use void* for it.. However now when it comes time to size the rects of each item in the grid (which I handle on WM_SIZE) I have a problem..

     void size( GRIDOBJECT* object, int index, int type, RECT rc ){
     	
     	int j = index;
     	while( j < (GRIDOBJECT)object->objects[index]->iNumObjects ){
     	  
     	  if( object->objects[j]->iType == 1 ){
     		object->objects[j]->rc.top = rc.bottom;
     		object->objects[j]->rc.bottom += rc.bottom-rc.top;
     		object->objects[j]->rc.left = rc.left;
     		object->objects[j]->rc.right = rc.right;
     	  }else{
     		object->objects[j]->rc.top = rc.bottom;
     		object->objects[j]->rc.bottom = rc.bottom-rc.top;
     		object->objects[j]->rc.left = rc.left;
     		object->objects[j]->rc.right = rc.right;
     		size(&object->objects[j], 0, 1, rc);
     	  }
     	  j++;
     	}
     	
     }

I call that for each of the GRIDOBJECT*stems in the MITH32GRIDSTRUCT struct. But I get an error because object->objects[] is a void* ...

void* is not a pointer-to-object type

What should I do?

[LuckY]

You can't index a void pointer directly because it is unknown to the compiler what the heck it's pointing to. That's what it's crying about.
Try casting it: ((LPRECT*)object->objects)[j]->rc...

[Mithoric]

I've tried casting all sorts of types but I still get the error (MingW).

[Mithoric]

This is the first line which gets the error --

while( j < object->objects[index]->iNumObjects ){

I've tried -

while( j < (int)object->objects[index]->iNumObjects ){

But to no avail.

[Ken Fitlike]

There are a number of different ways to go about this. Using the code you have, modify your 'size' function as follows ( create a temporary pointer to objects member of GRIDOBJECT and use that to access RECT member):

void size( GRIDOBJECT* object, int index, int type, RECT rc ){
      
  GRIDOBJECT *go=(GRIDOBJECT*)object->objects;
  int j = index;

  while( j < go[index].iNumObjects ){
     	  
    if( go[j].iType == 1 ){
    go[j].rc.top = rc.bottom;
    go[j].rc.bottom += rc.bottom-rc.top;
    go[j].rc.left = rc.left;
    go[j].rc.right = rc.right;
    }else{
    go[j].rc.top = rc.bottom;
    go[j].rc.bottom = rc.bottom-rc.top;
    go[j].rc.left = rc.left;
    go[j].rc.right = rc.right;
    size(&go[j], 0, 1, rc);
    }
    j++;
    }
  }

If you're compiling as c++ (which use of type 'bool' would seem to imply) then you should drop the 'typedef' from your struct definitions which would allow you to eliminate the void*, eg:

struct GRIDOBJECT_STRUCT{
  LPSTR             lpText,lpValue;
  int               id,iIndex,iNumObjects,iType,iValue;
  bool              bState,bValue;
  GRIDOBJECT_STRUCT *objects;
  RECT rc;
  };
 
GRIDOBJECT_STRUCT GRIDOBJECT;

You would obviously have to amend your other structure (MITH32GRIDSTRUCT) accordingly but at least you would be able to access the objects as you more or less originally intended.

[Mithoric]

I don't know why I have ever been using typedef but I changed the struct and it works great (apart from the operand problem by using -> instead of .

Thanks a bunch!