The following message-box styles are available.
MB_ABORTRETRYIGNORE The message box contains three pushbuttons: Abort, Retry, and Ignore.
MB_OK The message box contains one pushbutton: OK.
MB_OKCANCEL The message box contains two pushbuttons: OK and Cancel.
MB_RETRYCANCEL The message box contains two pushbuttons: Retry and Cancel.
MB_YESNO The message box contains two pushbuttons: Yes and No.
MB_YESNOCANCEL The message box contains three pushbuttons: Yes, No, and Cancel.
MB_APPLMODAL The user must respond to the message box before continuing work in the current window. However, the user can move to the windows of other applications and work in those windows. The default is MB_APPLMODAL if neither MB_SYSTEMMODAL nor MB_TASKMODAL is specified.
MB_SYSTEMMODAL All applications are suspended until the user responds to the message box. System-modal message boxes are used to notify the user of serious, potentially damaging errors that require immediate attention and should be used sparingly.
MB_TASKMODAL Similar to MB_APPLMODAL, but not useful within a Microsoft Foundation class application. This flag is reserved for a calling application or library that does not have a window handle available.