WinQueryClassName

This function copies the window class name, as a null-terminated string, into a buffer.

Syntax

WinQueryClassName(hwnd, lLength, PCHBuffer)

Parameters

hwnd (HWND) - input

Window handle.

If this window is of any of the preregistered WC_* classes the class name returned in the PCHBuffer parameter is in the form "#nnnnn", where "nnnnn" is a group of up to five digits that corresponds to the value of the WC_* class name constant.

lLength (LONG) - input

Length of PCHBuffer.

It must be greater than 0.

PCHBuffer (PCH) - output

Class name.

If the class name is longer than (lLength-1) only the first (lLength-1) characters of class name are copied.

Returns

lRetLen (LONG) - returns

Returned class name length.

This is the length, excluding the null-termination character.

Errors

Possible returns from WinGetLastError

PMERR_INVALID_HWND (0x1001)

An invalid window handle was specified.

PMERR_INVALID_STRING_PARM (0x100B)

The specified string parameter is invalid.

Example Code

This example obtains a pointer to the window procedure of the window class, given that we know the window handle.

#define INCL_WINWINDOWMGR

#include <OS2.H>

HAB       hab;
HWND      hwnd;
CLASSINFO classinfo;
PFNWP     pWindowProc;
char      *classname;

WinQueryClassName(hwnd,
                  sizeof(classname),
                  classname);

WinQueryClassInfo(hwnd,
                  classname,
                  &classinfo);

pWindowProc = classinfo.pfnWindowProc;

Definition

#define INCL_WINWINDOWMGR /* Or use INCL_WIN, INCL_PM, */
#include <os2.h>

HWND    hwnd;       /*  Window handle. */
LONG    lLength;    /*  Length of PCHBuffer. */
PCH     PCHBuffer;  /*  Class name. */
LONG    lRetLen;    /*  Returned class name length. */

lRetLen = WinQueryClassName(hwnd, lLength, PCHBuffer);

Related Functions

• WinCalcFrameRect
• WinCreateFrameControls
• WinCreateStdWindow
• WinCreateWindow
• WinDefWindowProc
• WinDestroyWindow
• WinQueryClassInfo
• WinRegisterClass
• WinSubclassWindow