Q34682: Communications (COM1:, COM2:) Receive Buffer Lost During CHAIN
Article: Q34682 Product(s): See article Version(s): 4.00 4.00b 4.50 Operating System(s): MS-DOS Keyword(s): ENDUSER | buglist4.00 buglist4.00b buglist4.50 B_BasicCom | mspl13_basic Last Modified: 8-FEB-1990 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. Microsoft has confirmed this to be a problem 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). The programs below demonstrate the problem: ' File: P1.BAS OPEN "com1:1200,e,7,1,cs,ds" FOR RANDOM AS #2 for x=1 to 10000 :next y=loc(2) print y; CHAIN "p2" '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 "com1:1200,e,7,1,cs,ds" for random as #1 print "start" for x=1 to 10000 print #1, x; next x close #1
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