HP 3000 Manuals HP 3000 Manuals
AT
Sets the breakpoint in a user program.
Syntax
AT {location} [ |EVERY| n |TIMES| ] [FOR { n } |TIMES| ]
{ NEXT } [ {ALL} ]
[DO [ command-list ] ]
[ (BREAK) ]
Parameters
Location Paragraph name, section name, subprogram name, function
name, procedure name, label name, or line number at
which you want your program to break. The location may
be referenced with an offset such as PROC#25.
The breakpoint is set immediately preceding the first
executable statement of the location you specify.
NEXT Specifies a breakpoint to be set at the beginning of the
next section, paragraph or procedure and every
succeeding section, paragraph or procedure. You cannot
abbreviate NEXT. In Pascal, a breakpoint is also set at
the end of every procedure.
EVERY n TIMES Specifies that the breakpoint you set will cause an
interruption every nth time it occurs. The interruption
occurs before the execution of the statement located at
the breakpoint. The default value of n is 1.
FOR n TIMES This clause specifies that the breakpoint be cleared
after it has executed n times, where n is an integer.
The default is to set a permanent breakpoint.
DO Specifies that one or more TOOLSET/XL commands be
performed when the breakpoint occurs. The default is to
BREAK and prompt you for your command.
Command-list Takes the form (command [; command] ...) where the
command is a TOOLSET/XL command.
Description
The AT command allows you to set up 15 active breakpoints in your user
program. When the breakpoint in your program is reached, control is
passed to the DO command list. If there is no DO command list, control
is passed to you through the TOOLSET/XL command interpreter.
You can specify that a TOOLSET/XL command(s) be performed when a
breakpoint occurs by using the DO command list parameter. If one of
these commands is the BREAK, RESUME, or SYSDEBUG command, the remainder
of the command list will be terminated when that command is executed;
otherwise, after all the commands in the list have been executed,
Symbolic Debug will execute a BREAK command.
Statement Number/Current Procedure (Pascal)
If you are setting a breakpoint at a location within the current
procedure, only the statement number needs to be specified. If the
breakpoint you are setting is outside of the current level 1 procedure,
the procedure or label name must be used as well.
Setting Breakpoints at Withs
Because the Pascal compiler generates the same statement number for a
WITH and its BEGIN statement, a breakpoint set at the WITH will be set at
the BEGIN statement.
In the following example, the breakpoint is logically set at statement
number 37 immediately before F2:=15; is executed.
>> AT #36
-->BREAKPOINT SET
Listing File
34 PROCEDURE P1;
35 BEGIN
36 WITH VAR1 DO
37 BEGIN
37 F2 := 15;
38 F1 := 5;
Breakpoints in Subroutines (FORTRAN)
You can set breakpoints anywhere inside a subroutine or function under
the same rules as for Pascal.
Example
COBOL
(1) >>AT MY-SUBP#112
Sets a breakpoint at line 112 in the subprogram MY-SUBP. The breakpoint
can be specified by the paragraph name as in example 2 or by line number
as in this example.
(2) >>AT PARA-1 OF MY-SUBP
Sets a breakpoint at line 112 in the subprogram MY-SUBP.
(3) >>AT COMP-COST FOR ALL DO (DISPLAY COST-CNTR; RESUME)
Sets a breakpoint at the paragraph heading COMP-COST in the current
program. The breakpoint will occur before the first executable statement
following COMP- COST. Every time COMP-COST is executed, the current value
of COST-CNTR will be displayed and your program will resume execution.
Pascal
(1) >>AT NEXT DO (DISPLAY F1;BREAK)
This example sets a breakpoint at the beginning and end of the next
procedure and every succeeding procedure. At each breakpoint, the value
of variable F1 is displayed and program execution is suspended. The same
result would occur if the BREAK was not included in the command list.
If you want execution to automatically resume after the value of F1 is
displayed, replace BREAK with RESUME in the command list above.
(2) >>AT PROC1.PROC2.PROC3.PROC4.
Sets a breakpoint at the beginning of the level 4 procedure PROC4.
(3) >>AT PROC1.PROC4
Sets a breakpoint at the beginning of the level 4 procedure. One only
needs full qualification as shown in example 2 when there is a duplicate
procedure name.
NOTE In Pascal, setting a breakpoint at a WHILE statement will return
control to Toolset only once, the first time the WHILE statement is
executed, even though the WHILE loop may be executed more than once
by the program. This is due to the machine instruction set of the
Precision Architecture.
FORTRAN
(1) >>AT SUBR1.15 DO (DISPLAY VAR1)
This example sets a breakpoint at the numeric label 15, within the
subroutine SUBR1, at which point it will display the contents of VAR1.