how to determine if an FTP "put" competed the transfer succesfully

I am using the connect ME 9210 with NET+OS 7.4.2.

I am creating a fairly simple FTP to serial gateway application.
This application uses FSRegisterSTOR to register a callback function which is called repeatedly for any file uploaded to the digi module via and FTP put command. My callback function save the data sent to it in ram and launches a thread to take the data stored and send it out the serial port.

All of the above is working fine when there are no errors. The problem I see is if there is an error in the FTP put (lost connection, or long delay before the file is completed) I can’t see how I can trap this error.

My question is how do I determine if a FTP file Put completed successfully or there was an error/break in the transfer?

Found it.

See NetOS74\src\bsp\fsintf\ftpsvrfs.c
int FS_DataSessionClosed(char * argp, unsigned long handle)