HP 3000 Manuals HP 3000 Manuals
BRK
The BRK function returns the status that BREAK and CONTROL Y (halt) had
before the BRK function was called. It can also change the status of
these, depending on the value of the argument passed. BRK is a Boolean
function that returns the value TRUE (one) or FALSE (zero).
Syntax
BRK (num_expr)
Parameters
num_expr This value determines whether BRK changes the status of
BREAK and CONTROL Y, as follows:
num_expr Status of BREAK and CONTROL Y
Negative Does not change status
Zero Disables both
Positive Enables both
The BRK function returns:
TRUE (one) If BREAK and CONTROL Y were enabled before the BRK
function was called.
FALSE (zero) If BREAK and CONTROL Y were disabled before the BRK
function was called.
When BREAK is enabled, pressing BREAK causes the operating system to
suspend HP Business BASIC/XL. The operating system command :RESUME
restarts HP Business BASIC/XL. If CONTROL Y is enabled and pressed and a
program is being executed, a message is printed indicating that HALT was
pressed and control is returned to the HP Business BASIC/XL interpreter.
If CONTROL Y is pressed while in the HP Business BASIC/XL interpreter,
only the message is printed.
When BREAK and CONTROLY are disabled, pressing either has no result.
Examples
10 Was_enabled=BRK(-1) !BRK does not change status
11 Was_enabled=BRK((10+10)-(10*10)) !BRK does not change status
20 Was_enabled=BRK(0) !Disables BREAK and CONTROL Y
21 Was_enabled=BRK((X-Y)-(X+(-Y))) !Disables BREAK and CONTROL Y
30 Was_enabled=BRK(1) !Enables BREAK and CONTROL Y
31 Was_enabled=BRK(ABS(X)) !Enables BREAK and CONTROL Y
!(if X != 0)
40 Was_enabled=BRK(X) !Action depends on value of X
50 IF BRK(X) THEN GOTO 100 !Action depends on value of X