Microsoft KB Archive/37347

= &quot;Device Unavailable&quot; on OPEN &quot;COM1: &quot; Compiled with BC /O/S =

Article ID: 37347

Article Last Modified on 11/21/2006



This article was previously published under Q37347



SYMPTOMS
A program that accesses the serial communications ports with OPEN &quot;COM1:&quot; or &quot;COM2:&quot; produces a &quot;Device Unavailable&quot; (run-time error 68) message if it is compiled using BC.EXE with the /O (stand-alone .EXE) and /S (minimize string space) options together.

To work around this limitation, do not use the /S and /O options together when compiling programs that access the communications ports.



STATUS
Microsoft has confirmed this to be a bug in Microsoft QuickBasic 4.00, 4.00b, and 4.50 for MS-DOS and in Microsoft Basic Compiler 6.00 and 6.00b (buglist6.00 buglist6.00b) for MS-DOS and MS OS/2. We are researching this problem and will post new information here as it becomes available. This problem does not occur in Microsoft Basic PDS Version 7.00 for MS-DOS and MS OS/2 (fixlist7.00).



MORE INFORMATION
The sample program below runs properly inside the environment; however, when compiled to an .EXE file using the BC /O and /S options, a &quot;Device Unavailable&quot; error message is produced on the OPEN &quot;COM1:&quot; statement. [The problem can also occur when you use the ON COM(n) GOSUB statement.]

The following is a code example: OPEN &quot;COM1:9600,N,8,1,CS,DS&quot; FOR RANDOM AS 1 CLOSE 1

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

Keywords: KB37347

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