INF: How to Test for Error When Using _bios_serialcom Service

ID Number: Q43401

5.00 5.10 6.00 6.00a 6.00ax

MS-DOS

docerr

Summary:

When using the _COM_RECEIVE function of _bios_serialcom() to read data

from a COM port, an error has occurred if bit 15, 11, 10, or 9 is set.

The documentation for Microsoft C version 5.1 is misleading and may be

interpreted that an error has occurred if any of the high-order bits

are set.

In fact, an error has occurred if, and only if, any of the following

four bits are set:

Bit Meaning If Set

--- --------------

15 Timed out

11 Framing error

10 Parity error

9 Overrun error

Further information concerning serial communications can be found in

Article 6 of "The MS-DOS Encyclopedia" (Interrupt-Driven

Communications) and in the book "The C Programmer's Guide to Serial

Communications" by Joseph Campbell, published by Howard W. Sams.

Additional reference words: 6.0 6.00 6.0a 6.00a 6.0ax 6.00ax quickc

2.0 2.00 2.01 2.5 2.50 2.51