QB 4.00b UPDATE.DOC: Adds SLEEP Statement to Suspend (33489)

SUMMARY

The following information was taken from the QuickBasic Version 4.00b UPDATE.DOC file. It describes features that have been added since Microsoft QuickBasic Version 4.00 was released.

This information applies to Microsoft QuickBasic Versions 4.00b and 4.50 for MS-DOS, to Microsoft Basic Compiler Versions 6.00 6.00b, and to Microsoft Basic PDS Version 7.00 for MS-DOS and MS OS/2.

MORE INFORMATION

New Statement: SLEEP
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Action: Suspends the execution of a Basic program

Syntax: SLEEP <seconds>

Remarks:

In this syntax the optional parameter <seconds> determines how many
seconds to suspend the program. SLEEP suspends a QuickBasic program
until one of the following three events occurs:

1. The time period specified in the SLEEP statement has elapsed.

2. A key is pressed.

3. An enabled QuickBasic event occurs.

A QuickBasic event is one that you can trap with an ON <event>
statement such as ON COM or ON KEY. Note that a QuickBasic event does
not interrupt the suspension caused by SLEEP unless its trap is active
when the event occurs. That is, the trap must have been set up with an
ON <event> statement, turned on with an <event> ON statement, and not
disabled with <event> OFF or <event> STOP. Note, too, that SLEEP
responds only to actual keystrokes that occur after the SLEEP
statement executes; SLEEP ignores characters that were stored in the
keyboard buffer before the SLEEP statement executes.

If you execute SLEEP with a time period of 0 (zero), or without
specifying any time period, the program is suspended for an indefinite
period. In this case, only a keystroke or QuickBasic event can
interrupt the suspension.

Example:

The following program suspends its execution for 20 seconds. Because
the sample program has no ON EVENT statement, the only way to
interrupt its suspension prior to the end of the 20-second delay is by
pressing a key.

   PRINT "Taking a twenty-second timeout..."
   SLEEP 20
   PRINT "Play ball!"