tron - turn on execution tracing
troff - turn off execution tracing
are debugging aids.
turns on tracing and
turns it off.
When tracing is on, each program line number is printed within square brackets
as it is executed.
Unnumbered lines are displayed as having line number 0.
20 i = 11
30 for j = 1 to 2
40 k = i + 10
50 print i; j; k
60 i = i + 10
produces the output
 11 1 21
 21 2 31
This example uses
to trace execution of a loop.
The numbers in brackets are line numbers which constitute the trace.
All other output is produced by the
statement in the program.
If the program is compiled with the "-L" option,
may not be used.
The "-L" option is used to decrease the size of the compiled Basmark QuickBASIC
program by omitting information about program line numbers at run-time.
The Basmark QuickBASIC Programmerís Manual