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If a message box has a Cancel button, the function returns the IDCANCEL value if either the ESC key is pressed or the Cancel button is selected. If the message box has no Cancel button, pressing ESC has no effect.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
If the function succeeds, the return value is one of the following menu-item values.
Return code/value Description
IDABORT
3
The Abort button was selected.
IDCANCEL
2
The Cancel button was selected.
IDCONTINUE
11
The Continue button was selected.
IDIGNORE
5
The Ignore button was selected.
IDNO
7
The No button was selected.
IDOK
1
The OK button was selected.
IDRETRY
4
The Retry button was selected.
IDTRYAGAIN
10
The Try Again button was selected.
IDYES
6
The Yes button was selected.