Q65548: PDS 7.10 Can Now Buffer COM1 or COM2 Input Data During a SHELL

Article: Q65548
Product(s): See article
Version(s): 7.10   | 7.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | SR# S900904-18 B_QuickBas | mspl13_basic
Last Modified: 21-SEP-1990

In most versions of Microsoft BASIC Compiler and QuickBASIC, during a
SHELL, data coming in through the communications port is not buffered
and is lost. A new feature of Microsoft BASIC Professional Development
System (PDS) version 7.10 allows programs compiled with the BC /O
(stand-alone) option to continue to buffer communications input during
a SHELL. However, programs that use the run-time module with BASIC PDS
7.10 still cannot handle COM1 or COM2 input during a SHELL.

This information applies to Microsoft BASIC PDS 7.10 for MS-DOS and MS
OS/2. The above feature is not available in the following products:
Microsoft QuickBASIC versions 1.00, 1.01, 1.02, 2.00, 2.01, 3.00,
4.00, 4.00b, and 4.50 for MS-DOS; Microsoft BASIC Compiler versions
6.00 and 6.00b for MS-DOS and MS OS/2; and Microsoft BASIC PDS version
7.00 for MS-DOS and MS OS/2.

This feature is available only when you compile with BC /O. The /O
compiler switch causes the program to be completely stand alone, which
means it will run without the run-time module. This feature is not
available with the run-time module because the run-time module is
taken out of memory during a SHELL and reloaded when the SHELL is
exited. Since the code for communications support is contained in the
run-time module, it is not available during the SHELL. Therefore, the
program cannot continue to buffer the communications data because the
code that supports communications has been removed from memory. With a
stand-alone program, the code for communications support is directly
linked to the program and stays in memory, thus allowing the program
to continue to buffer communications data during a SHELL.

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