Windows API Reference

MessageBoxW Function

Signature:

int MessageBoxW(
  [in, optional] HWND    hWnd,
  [in, optional] LPCWSTR lpText,
  [in, optional] LPCWSTR lpCaption,
  [in]           UINT    uType
);

Parameters

• hWnd [in, optional]
  A handle to the owner window of the message box to be created. If this parameter is NULL, the message box has no owner window.
• lpText [in, optional]
  A null-terminated string that contains the message to be displayed.
• lpCaption [in, optional]
  A null-terminated string that specifies the title of the window. If this parameter is NULL, the title is the string "Error".
• uType [in]
  A variable of type UINT that specifies the content and behavior of the dialog box. This parameter can be a combination of flags from the following message box flags categories.

Return Value

• If the function succeeds, the return value is one of the following menu-defined values: IDOK, IDCANCEL, IDABORT, IDRETRY, IDIGNORE, IDYES, IDNO, IDCLOSE, IDHELP.
• If the function fails, the return value is less than or equal to zero. For extended error information, call GetLastError.

Remarks

The MessageBoxW function creates, displays, and operates a message box. A message box is a dialog box that displays a specific message to the user and prompts for a response.

The uType parameter determines the buttons displayed, the icon displayed, which control has the keyboard focus, and the modality of the message box. See the Message Box Flags documentation for a complete list of options.

Requirements

Header: winuser.h (include windows.h)
Library: User32.lib
DLL: User32.dll

See Also

• MessageBoxA
• Message Box Flags
• DialogBox

#include <windows.h>

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    MessageBoxW(NULL, L"This is a simple message box.", L"My Application", MB_OK | MB_ICONINFORMATION);
    return 0;
}