CPI-C Accept_Conversation (cmaccp) Does Not Block As Expected

ID: Q184505


The information in this article applies to:
  • Microsoft SNA Server, versions 2.0, 2.1, 2.11, 3.0, 4.0


SYMPTOMS

If a CPI-C (Common Programming Interface for Communications) application calls WinCPICStartup followed by Accept_Conversation (cmaccp), then the cmaccp() will function in blocking mode. However, the cmaccp() will never complete, because no local TP (transaction processing) name has been specified for the application.

In order to associate a TP (Transaction Program) name with the cmaccp() call, Specify_Local_TP_Name (cmsltp) must be called prior to cmaccp(). However, this causes cmaccp() to function in "non-blocking" mode. This can cause the cmaccp() to fail immediately with an error 25 (CM_PROGRAM_STATE_CHECK) instead of waiting for an incoming attach request.


CAUSE

This behavior is by design, according to the Windows CPI-C specification.


RESOLUTION

To force blocking behavior of cmaccp, Wait_For_Conversation (cmwait) must be called after cmsltp() and cmaccp() in order to cause the application's thread to block. All CPI-C functions operate in blocking mode by default, except the cmaccp() function, which requires the application to call cmwait() in order to force blocking behavior.

There are no plans to change the Windows CPI-C specification or to modify the SNA Server CPI-C API (application programming interface) to behave differently than it does in the current design.

Additional query words:

Keywords : snacpic
Version : WINDOWS:2.0,2.1,2.11,3.0,4.0
Platform : WINDOWS
Issue type : kbprb


Last Reviewed: October 4, 1999
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