EndDialog

EndDialog is a Windows API function used to terminate a modal dialog box and return a result to the caller that created the dialog. It is part of the Win32 API and is typically declared as VOID EndDialog(HWND hDlg, INT_PTR nResult). The hDlg parameter identifies the dialog box to close, and nResult is the value that will be returned by the function that created the dialog (such as DialogBox or DialogBoxParam).

When EndDialog is called, the dialog’s message loop ends, the dialog window is destroyed, and execution returns to the point after the dialog creation call, with DialogBox returning the specified nResult. This mechanism allows a dialog procedure to signal the outcome of the user’s interaction, such as acceptance or cancellation.

Usage generally occurs within a dialog procedure in response to user actions. Common practice is to call EndDialog with a result corresponding to the action chosen by the user, for example EndDialog(hDlg, IDOK) when the user confirms, or EndDialog(hDlg, IDCANCEL) when the user cancels. The values IDOK and IDCANCEL are standard command identifiers used to convey these outcomes.

EndDialog is intended for modal dialogs created with functions like DialogBox, DialogBoxParam, or DialogBoxIndirectParam. It is not applicable to modeless dialogs, where different lifecycle and messaging patterns apply. The function is defined in user32.dll and has been part of the Windows API for many versions, ensuring compatibility across Windows releases. See also DialogBox, DialogBoxParam, and DialogBoxIndirectParam for related dialog creation and control flow.