Microsoft KB Archive/34682

= Communications (COM1:, COM2:) Receive Buffer Lost During CHAIN =

Article ID: 34682

Article Last Modified on 11/21/2006

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APPLIES TO


 * Microsoft QuickBasic 4.0
 * Microsoft QuickBASIC 4.0b
 * Microsoft QuickBasic 4.5 for MS-DOS
 * Microsoft BASIC Compiler 6.0
 * Microsoft BASIC Compiler 6.0b

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This article was previously published under Q34682



SYMPTOMS
The communications receive buffer is cleared when chaining to another module; at this point, data can be lost. This problem occurs only in a compiled .EXE program, and does not occur in the QB.EXE editor. Compiling with the BC /d (debug) option does not help. Data received at the communications port after the CHAIN operation is received normally.



STATUS
Microsoft has confirmed this to be a bug in Microsoft QuickBasic Versions 4.00, 4.00b, and 4.50, and in Microsoft Basic Compiler Versions 6.00 and 6.00b for MS-DOS and MS OS/2 (buglist6.00, buglist6.00b). This problem was corrected in Microsoft Basic Professional Development System (PDS) Version 7.00 (fixlist7.00).



MORE INFORMATION
The programs below demonstrate the problem: ' File: P1.BAS OPEN &quot;com1:1200,e,7,1,cs,ds&quot; FOR RANDOM AS #2 for x=1 to 10000 :next y=loc(2) print y;  CHAIN &quot;p2&quot;    'Chain to second program and print out buffer size

' File: P2.BAS a$=input$(loc(2),2) print a$;

' File:P.bas 'This program will send the characters open &quot;com1:1200,e,7,1,cs,ds&quot; for random as #1 print &quot;start&quot; for x=1 to 10000 print #1, x;  next x   close #1

Additional query words: QuickBas BasicCom buglist4.00 buglist4.00b buglist4.50 B_BasicCom

Keywords: KB34682

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