GetClassInfoA function (winuser.h)
Retrieves information about a window class.
Syntax
BOOL GetClassInfoA(
[in, optional] HINSTANCE hInstance,
[in] LPCSTR lpClassName,
[out] LPWNDCLASSA lpWndClass
);
Parameters
[in, optional] hInstance
Type: HINSTANCE
A handle to the instance of the application that created the class. To retrieve information about classes defined by the system (such as buttons or list boxes), set this parameter to NULL.
[in] lpClassName
Type: LPCTSTR
The class name. The name must be that of a preregistered class or a class registered by a previous call to the RegisterClass or RegisterClassEx function.
Alternatively, this parameter can be an atom. If so, it must be a class atom created by a previous call to RegisterClass or RegisterClassEx. The atom must be in the low-order word of lpClassName; the high-order word must be zero.
[out] lpWndClass
Type: LPWNDCLASS
A pointer to a WNDCLASS structure that receives the information about the class.
Return value
Type: BOOL
If the function finds a matching class and successfully copies the data, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
Remarks
Note
The winuser.h header defines GetClassInfo as an alias that automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that is not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | winuser.h (include Windows.h) |
| Library | User32.lib |
| DLL | User32.dll |
| API set | ext-ms-win-ntuser-windowclass-l1-1-0 (introduced in Windows 8) |
See also
Conceptual
Reference