CommDlgExtendedError defined in commdlg.h but missing from library

Posted by The PocketTV Team on December 14, 2006, 2:33 am

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This is a bug report. MSFT, please take note of it.

CommDlgExtendedError is defined in commdlg.h but missing from WM5 libraries.

this is a problem since the return value of some UI dialogs, e.g.
GetOpenFileName, can only be interpreted correctly by calling
CommDlgExtendedError.

see
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/userinput/commondialogboxlibrary/commondialogboxreference/commondialogboxfunctions/getopenfilename.asp

a zero value returned by GetOpenFileName can be an error case, or it can
just mean that the user selected no file in the dialog or hit "Cancel".

currently there is no good way to test the error case when GetOpenFileName
returns 0, since GetOpenFileName does not clear the "GetLastError" code in
the case of no-error. In other terms, when GetOpenFileName returns 0,
GetLastError can return a non-zero value (like 6 = invalid handle"), while
in fact no error occured.

a dirty work-around is to clear the GetLastError error-code immediateky
before calling GetOpenFileName, and hope it will be set to a non-zero value
by GetOpenFileName only if a real error occurs in GetOpenFileName.

Posted by The PocketTV Team on December 14, 2006, 2:41 am

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actually this does not even work: GetOpenFileName sets GetLastError to 6
(Invalid Handle) on a WM5 Smartphone (Samsung Blackjack) when the dialog is
cancelled using the BACK key.

so it looks like there is no way to correctly detect the error case...