Tandy 1000 Basic Reference Manual page 228

ChaDter 10 I BASIC
Kevwords
ON COM(
)
GOSUB
Statement
ON COM(channeZ) GOSUB
line
Transfers program control to a subroutine beginning at
line
when activity occurs on the communication channel.
Channel selects communications Channel 1 or 2.
Line is the first line of the subroutine to be executed when activ-
ity occurs on the specified communications channel. If you spec-
ify Line 0, you t u r n off communications trapping. Use the
RETURN statement to exit the subroutine.
BASIC executes the ON COM(
)
GOSUB statement only if a
COM( ON statement has been previously executed to enable
communication trapping. If a COM(
)
STOP statement has been
issued to halt communication trapping temporarily, BASIC exe-
cutes the subroutine immediately after the next
COM(
1
ON
statement.
When you execute the
ON
COM(
)
GOSUB statement, BASIC
immediately issues a COM(
1
STOP statement to prevent recur-
sive traps. When BASIC executes the RETURN from the subrou-
tine, it automatically executes another COM(
)
ON statement t o
enable communication trapping again, unless the subroutine exe-
cutes a COM(
OFF
statement.
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