Via Systems

Technical Bulletin



Summary: AP/UX when used with a TCP/IP connection outputs spurious nul characters immediately after a valid CR character.
ViaDuct 3.X



Symptom:

When communicating with the host system and the carriage return is pressed, nul characters are sent.

Problem:

The NUL character can occur in the middle of a cursor-positioning or other control character sequence thus causing incorrect display of the HOST screen (e.g. misplaced cursor or characters).

The NUL character is included in "Capture:Record" output, causing an invalid newline (CR NUL LF) to be recorded. These can have unwanted side effects (since CR NUL can validly appear in AP output) so they are not enabled by default. Via Duct does contain a work-around for both of these problems.

Solution:

  1. To correct the problem of incorrect cursor positioning with terminal type "PC MONITOR", add the following line to the [Special] section of the VIADUCT.INI file:
    [Special]
    PCMonitorStripNULS=1
  2. To fix the problem of NULs appearing in Captured data, add the following line to the [Special] section of the VIADUCT.INI file:
    [Special]
    CaptureStripNULS=1

10 Oct 1995 mls
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