MessageBox - Windows API Reference

Synopsis


int MessageBox(
  HWND hWnd,           // Handle to the window to display the message box.
  LPCTSTR lpText,      // The text to display in the message box.
  HWND hIcon,          // Optional. An icon to display in the message box.
  INT_PTR uType       // Flags that control the appearance and behavior of the message box.
);

Parameters

hWnd

HWND

The handle of the window to display the message box. If hWnd is NULL, the message box is displayed in the first active window.

lpText

LPCTSTR

A C-style string literal that specifies the text to display in the message box.

hIcon

HWND

An optional icon to display in the message box.

uType

INT_PTR

Flags that control the appearance and behavior of the message box. These flags are defined in MessageBoxFunction. The following flags are available:

MB_OK: Displays an OK button.
MB_CANCEL: Displays an OK and a Cancel button.
MB_ICONOK: Displays an OK button and an icon.
MB_ICONCANCEL: Displays an OK button and a Cancel button with a closed circle icon.
MB_ICONERROR: Displays an OK button and a closed circle icon with an error icon.
MB_ICONQUESTION: Displays an OK and a Cancel button with a question mark icon.
MB_SYSTEM_MODAL: The message box is modal.
MB_APPLICATION_MODAL: The message box is modal, but the application can respond to the WM_QUERYPOS and WM_INITDIALOG messages.

Returns


INT_PTR

The return value of this function depends on the user’s action:

MB_OK or MB_ICONOK: Returns MB_OK.
MB_OK or MB_ICONOK or MB_OK or MB_ICONOK: Returns MB_OK.
MB_CANCEL or MB_ICONCANCEL or MB_ICONCANCEL or MB_ICONCANCEL: Returns MB_OK.
The user clicks the Cancel button: Returns MB_CANCEL.
The user clicks the Close button: Returns 0.

Example


            // Example code to display a message box with an OK button.
            MessageBox( hWnd, "Hello, world!", NULL, MB_OK );