Knowledge Base

Windows 3.x APPC Application Fails with F002 (AP_TP_BUSY) Error

Article ID: 137246

Article Last Modified on 12/8/2003

APPLIES TO

Microsoft SNA Server 2.0, when used with:
- Microsoft Windows NT 4.0
Microsoft SNA Server 2.1, when used with:
- Microsoft Windows NT 4.0
Microsoft SNA Server 3.0, when used with:
- Microsoft Windows NT 4.0

This article was previously published under Q137246

SYMPTOMS

The Microsoft SNA Server APPC Programmer's Reference documents the following reason for a primary return code of F002 (AP_TP_BUSY) error:

F002 AP_TP_BUSY

The Local TP has issued a call to APPC while APPC was processing another call for the same TP. This may occur if the local TP has multiple threads, and more than one thread is issuing APPC calls using the same tp_id.

However, this is not the only possible cause of this error when running the Windows 3.x client. The SNA Server Windows 3.x APPC interface also returns AP_TP_BUSY (primary return code = F002) to an application if it calls into the APPC interface from a Windows procedure from SendMessage().

Applications that talk over the CPIC interface may also encounter this problem because the CPIC API communicates over the APPC API. If this APPC error is returned to the CPIC interface as a result of a CMINIT call, CPIC returns Error 20 (product specific error) to the application. To see if this error is occurring, SNA Server Windows 3.x CPIC and APPC API tracing must be enabled. For additional information, please see the following article(s) in the Microsoft Knowledge Base:

123256 Enabling SNA Server Windows 3.x Client Traces

Some third party applications require do not run reliably on the SNA Server Windows 3.x client software unless the TP_BUSY check is disabled. Wall Data Rumba AS/400 Shared Folders requires that the TP_BUSY check is disabled.

CAUSE

This additional TP_BUSY check is done by the APPC interface to prevent a possible deadlock within Windows.

RESOLUTION

Using the SNA Server 2.11 Windows 3.x client software, the following parameter can be set in the [wnap] section of WIN.INI file to disable this SendMessage check:

SendMessageCheck=NO

The SNA Server Windows client process (WNAP) must be stopped and started to enable this change.

WARNING: This parameter should be used with caution, since it can lead to deadlocks from within Windows, depending on the other Windows applications that are running on the computer.

STATUS

Microsoft has implemented this setting within the SNA Server 2.11 Windows client software. SNA Server 2.0 and 2.1 customers should upgrade to SNA Server 2.11.

Additional query words: prodsna 2.00 2.10 2.11 tp_busy F002

Keywords: kbbug kbfix KB137246

Microsoft KB Archive/137246

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