Twain always returns TWRC_NOTDSEVENT -

i use twain 2.3 (twaindsm.dll) in application hp scanjet 200 twain protocol 1.9.

my twaiin calls are:

opendsm: dg_control, dat_parent, msg_opendsm  opends: dg_control, dat_identity, msg_opends  enableds: dg_control, dat_userinterface, msg_enableds  processdeviceevent: dg_control, dat_event, msg_processevent 

and result of last call allways twrc_notdsevent instead of twrc_dsevent.

could please this?

once use dg_control / dat_event / msg_processevent, messages applications message loop must sent data source processing. receiving twrc_notdsevent means forwarded message isn't source application should process normal.

keep forwarding messages source until receive msg_xferready means there data transfer. once transfer finished , have sent msg_disableds that's when can stop forwarding messages source.