BUG: Basic Serial Communications Programs May Hang w/ No Error (94007)


The information in this article applies to:

  • Microsoft Visual Basic for MS-DOS
  • Microsoft Basic Professional Development System for MS-DOS 7.0
  • Microsoft Basic Professional Development System for MS-DOS 7.1
  • Microsoft QuickBASIC 4.0
  • Microsoft QuickBASIC 4.0b
  • Microsoft QuickBASIC 4.5
This article was previously published under Q94007

SYMPTOMS

Programs using Basic's built-in serial communications may hang after several minutes or hours of continuous use, even though no communication error has occurred.

WORKAROUND

Use one of the following methods to work around this problem:

  • Lower the baud rate until the program stops hanging.
  • Try the suggestions listed in the following article in the Microsoft Knowledge Base:

    39342How to Solve Common QuickBasic Communications Port Problems

  • Use a third-party communications library instead of Basic's communications capability. Some third-party serial communications libraries are listed below. Microsoft provides this information for your convenience only and does not endorse these third-party products: 
       Company              Product                 Phone
   --------------------------------------------------------
   Microhelp            Comm. Library for DOS   (800) 922-3383
   Crescent Software    PDQCOMM                 (800) 352-2742
   Software Interphase  QuickComm               (800) 542-2742
   Teratech             Telecom Toolkit         (301) 424-3903

STATUS

Microsoft has confirmed this to be a bug in the Standard and Professional Editions of Microsoft Visual Basic for MS-DOS, version 1.0; in Microsoft Basic Professional Development System (PDS) for MS-DOS, version 7.1 (buglist7.10); and in Microsoft QuickBasic for MS-DOS, version 4.5 (buglist4.50). We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

After a compiled program hangs, you may be able to press CTRL+BREAK to stop the program in the interpreter environment or while running the program if you compiled it for run-time error checking (BC /D).
Modification Type:MinorLast Reviewed:8/16/2005
Keywords:kbbug KB94007
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