NET/MASTER Network Control Language (NCL) Programmer's Guide

Using Breakpoints to Suspend Execution
Debugging an NCL Process
9–44 106160 Tandem Computers Incorporated
Using Breakpoints to
Suspend Execution
A breakpoint is a position in an NCL process at which NCL suspends execution. You
typically set a breakpoint in the source code where you think a bug is located, by using
the DEBUG BREAKPOINT command. When working with breakpoints, you can:
Set breakpoints in an NCL process, by using the DEBUG BREAKPOINT
command.
List breakpoints in an NCL process, by using the DEBUG LIST BREAKPOINTS
command.
Clear breakpoints in an NCL process, by using the DEBUG CLEAR BREAKPOINT
command.
Setting Breakpoints The DEBUG BREAKPOINT command sets breakpoints. You can place a breakpoint at
the following positions in an NCL process:
At the first statement of an error handler.
At the entrance or exit statement to an internal or external procedure or function.
At a specified statement: either in the current procedure or function, or in a nested
procedure or function in the current procedure or function, or in an external
procedure.
At the termination point of an NCL process.
At the specified variable for the specified type of access: for read access, for write
access, or for either. (Write access includes deletion: that is, assigning a null value
to a variable.)
Note When setting a breakpoint on a variable, you must omit the leading ampersand (&) from the variable
name.
Each breakpoint set in an NCL process is allocated a unique number, starting from 1
and incrementing by 1 through to the maximum number of breakpoints you can set in
a single debug session: 65535. A breakpoint number is not reallocated if a breakpoint
is later cleared. Accordingly, if you set 65535 breakpoints in a debug session and you
clear one breakpoint, you will be unable to set any more breakpoints in the session.