Protocol errors occur when an ATMI function is invoked, either in the wrong order or using an incorrect process. For example, a client may try to begin communicating with a server before joining the application. Or tpcommit() may be called by a transaction participant instead of the initiator.

You can correct a protocol error at the application level by enforcing the rules of order and proper usage of ATMI calls.

To determine the cause of a protocol error, answer the following questions:

• Is the call being made in the correct order?
• Is the call being made by the correct process?

Protocol errors return the TPEPROTO value in tperrno(5).

Refer to “Introduction to the C Application-Transaction Monitor Interface” in the Oracle Tuxedo ATMI C Function Reference for more information.