tagCREATESTRUCTA structure

Defines the initialization parameters passed to the window procedure of an application. These members are identical to the parameters of the CreateWindowEx function.

Syntax

typedef struct tagCREATESTRUCTA {
  LPVOID    lpCreateParams;
  HINSTANCE hInstance;
  HMENU     hMenu;
  HWND      hwndParent;
  int       cy;
  int       cx;
  int       y;
  int       x;
  LONG      style;
  LPCSTR    lpszName;
  LPCSTR    lpszClass;
  DWORD     dwExStyle;
} CREATESTRUCTA, *LPCREATESTRUCTA;

Members

lpCreateParams

Type: LPVOID

Contains additional data which may be used to create the window. If the window is being created as a result of a call to the CreateWindow or CreateWindowEx function, this member contains the value of the lpParam parameter specified in the function call.

If the window being created is a MDI client window, this member contains a pointer to a CLIENTCREATESTRUCT structure. If the window being created is a MDI child window, this member contains a pointer to an MDICREATESTRUCT structure.

If the window is being created from a dialog template, this member is the address of a SHORT value that specifies the size, in bytes, of the window creation data. The value is immediately followed by the creation data. For more information, see the following Remarks section.

hInstance

Type: HINSTANCE

A handle to the module that owns the new window.

hMenu

Type: HMENU

A handle to the menu to be used by the new window.

hwndParent

Type: HWND

A handle to the parent window, if the window is a child window. If the window is owned, this member identifies the owner window. If the window is not a child or owned window, this member is NULL.

cy

Type: int

The height of the new window, in pixels.

cx

Type: int

The width of the new window, in pixels.

y

Type: int

The y-coordinate of the upper left corner of the new window. If the new window is a child window, coordinates are relative to the parent window. Otherwise, the coordinates are relative to the screen origin.

x

Type: int

The x-coordinate of the upper left corner of the new window. If the new window is a child window, coordinates are relative to the parent window. Otherwise, the coordinates are relative to the screen origin.

style

Type: LONG

The style for the new window. For a list of possible values, see Window Styles.

lpszName

Type: LPCTSTR

The name of the new window.

lpszClass

Type: LPCTSTR

A pointer to a null-terminated string or an atom that specifies the class name of the new window.

dwExStyle

Type: DWORD

The extended window style for the new window. For a list of possible values, see Extended Window Styles.

Remarks

Because the lpszClass member can contain a pointer to a local (and thus inaccessable) atom, do not obtain the class name by using this member. Use the GetClassName function instead.

You should access the data represented by the lpCreateParams member using a pointer that has been declared using the UNALIGNED type, because the pointer may not be DWORD aligned. This is demonstrated in the following example:

typedef struct tagMyData 
{
    // Define creation data here. 
} MYDATA; 
 
typedef struct tagMyDlgData 
{ 
    SHORT   cbExtra; 
    MYDATA  myData; 
} MYDLGDATA, UNALIGNED *PMYDLGDATA; 
 
PMYDLGDATA pMyDlgdata = (PMYDLGDATA) (((LPCREATESTRUCT) lParam)->lpCreateParams);

Requirements

   
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Header winuser.h (include Windows.h)

See Also

About the Multiple Document Interface

Conceptual

CreateWindow

CreateWindowEx

MDICREATESTRUCT

Reference

Windows