In my code this function is called:
SPErr err = sPSActionControl->Play(
&result,
eventID, // for a automation plugin "ABC"
NULL,
plugInDialogDisplay); // show dialog
It's the same thing calling that Play() as clicking "File - automate - ABC", a modal dialog appears. The document tells when successfully invoking the Play() function, the return value is kSPNoError (zero). But in the modal dialog, if clicking "OK" or "Cancel" button to close the dialog ( sADMDialog->EndModal(dlgRef, 0, true/false) ), the return value of Play() is userCanceledErr (-128), this occurs in CS5. The same plugin installed on CS6 prebuild edition, then the return value is kSPNoError (zero). It seems the different SDK leads to different result.
Could any body tell me the details about its return value? Thanks.