HP-UX SNAplus2 CPI-C Programmer's Guide (June 2003)

CPI-C Calls
Send_Error (cmserr)
Chapter 3228
Send-Pending State
If the conversation is in Send-Pending state, the local program can issue
the Set_Error_Direction call to specify whether the error being reported
resulted from the received data or from the processing of the local
program after successfully receiving the data.