IDABORT Abort button was selected.
IDCANCEL Cancel button was selected.
IDIGNORE Ignore button was selected.
IDNO No button was selected.
IDOK OK button was selected.
IDRETRY Retry button was selected.
IDYES Yes button was selected
Zero if there is not enough memory to display the message box; otherwise one of the following values is returned:
IDABORT The Abort button was selected.
IDCANCEL The Cancel button was selected.
IDIGNORE The Ignore button was selected.
IDNO The No button was selected.
IDOK The OK button was selected.
IDRETRY The Retry button was selected.
IDYES The Yes button was selected.
If a message box has a Cancel button, the IDCANCEL value will be returned if either the ESC key is pressed or the Cancel button is selected. If the message box has no Cancel button, pressing the ESC key has no effect.