Displays the current value of a program variable or language
expression in the monitor view of the VSI DECwindows Motif for
OpenVMS user interface.
NOTE
Requires the VSI DECwindows Motif for OpenVMS user interface.
Format
MONITOR expression
1 – Parameters
expression
Specifies an entity to be monitored. With high-level languages,
this is typically the name of a variable. Currently, MONITOR does
not handle composite expressions (language expressions containing
operators).
If you specify the name of an aggregate variable (a composite
data structure such as an array or record structure), the monitor
view lists "Aggregate" for the value of the variable. You can
then double-click on the variable name to get the values of all
the elements (see context-sensitive Help).
To specify an individual array element, array slice, or record
component, follow the syntax of the current language.
2 – Qualifiers
2.1 /ASCIC
/ASCIC
/AC
Interprets each monitored entity as a counted ASCII string
preceded by a 1-byte count field that gives the length of the
string. The string is then displayed.
2.2 /ASCID
/ASCID
/AD
Interprets each monitored entity as the address of a string
descriptor pointing to an ASCII string. The CLASS and DTYPE
fields of the descriptor are not checked, but the LENGTH and
POINTER fields provide the character length and address of the
ASCII string. The string is then displayed.
2.3 /ASCII
/ASCII:n
Interprets and displays each monitored entity as an ASCII string
of length n bytes (n characters). If you omit n, the debugger
attempts to determine a length from the type of the address
expression.
2.4 /ASCIW
/ASCIW
/AW
Interprets each monitored entity as a counted ASCII string
preceded by a 2-byte count field that gives the length of the
string. The string is then displayed.
2.5 /ASCIZ
/ASCIZ
/AZ
Interprets each monitored entity as a zero-terminated ASCII
string. The ending zero byte indicates the end of the string.
The string is then displayed.
2.6 /BINARY
Displays each monitored entity as a binary integer.
2.7 /BYTE
Displays each monitored entity in the byte integer type (length 1
byte).
2.8 /DATE_TIME
Interprets each monitored entity as a quadword integer (length 8
bytes) containing the internal OpenVMS representation of date and
time. Displays the value in the format dd-mmm-yyyy hh:mm:ss.cc.
2.9 /DECIMAL
Displays each monitored entity as a decimal integer.
2.10 /DEFAULT
Displays each monitored entity in the default radix.
2.11 /EXTENDED_FLOAT
(Alpha and Integrity servers only) Displays each monitored entity
in the IEEE X_floating type (length 16 bytes).
2.12 /FLOAT
On VAX processors, displays each monitored entity in the F_
floating type (length 4 bytes).
On Alpha processors, displays each monitored entity in the IEEE
T_floating type (double precision, length 8 bytes).
2.13 /G_FLOAT
Displays each monitored entity in the G_floating type (length 8
bytes).
2.14 /HEXADECIMAL
Displays each monitored entity as a hexadecimal integer.
2.15 /INSTRUCTION
Displays each monitored entity as an assembly-language
instruction (variable length, depending on the number of
instruction operands and the kind of addressing modes used).
See also the /OPERANDS qualifier.
2.16 /INT
Same as /LONGWORD qualifier.
2.17 /LONG_FLOAT
(Alpha and Integrity servers only) Displays each monitored entity
in the IEEE S_floating type (single precision, length 4 bytes).
2.18 /LONG_LONG_FLOAT
(Alpha and Integrity servers only) Displays each monitored entity
in the IEEE T_floating type (double precision, length 8 bytes).
2.19 /LONGWORD
/LONGWORD
/INT
/LONG
Displays each monitored entity in the longword integer type
(length 4 bytes). This is the default type for program locations
that do not have a compiler-generated type.
2.20 /OCTAL
Displays each monitored entity as an octal integer.
2.21 /OCTAWORD
Displays each monitored entity in the octaword integer type
(length 16 bytes).
2.22 /QUADWORD
Displays each monitored entity in the quadword integer type
(length 8 bytes).
2.23 /REMOVE
Removes a monitored item or items with the address expression
specified from the Monitor View.
2.24 /SHORT
Same as /WORD qualfier.
2.25 /TASK
Applies to tasking (multithread) programs. Interprets each
monitored entity as a task (thread) object and displays the task
value (the name or task ID) of that task object. When monitoring
a task object, use /TASK only if the programming language does
not have built-in tasking services.
2.26 /WORD
/WORD
/SHORT
Displays each monitored entity in the word integer type (length 2
bytes).
3 – Description
You can use the MONITOR command only with the debugger's VSI
DECwindows Motif for OpenVMS user interface, because the output
of that command is directed at the monitor view. With the command
interface, you typically use the EVALUATE, EXAMINE or SET WATCH
command instead.
The MONITOR command does the following:
1. Displays the monitor view (if it is not already displayed by a
previous MONITOR command).
2. Puts the name of the specified variable or expression and its
current value in the monitor view.
The debugger updates the monitor view whenever the debugger
regains control from the program, regardless of whether the value
of the variable or location you are monitoring has changed. (By
contrast, a watchpoint halts execution when the value of the
watched variable changes.)
For more information about the monitor view and the MONITOR
command, see context-sensitive Help.
Related commands:
DEPOSIT
EVALUATE
EXAMINE
SET WATCH
4 – Example
DBG> MONITOR COUNT
This command displays the name and current value of the
variable COUNT in the monitor view of the debugger's VSI
DECwindows Motif for OpenVMS user interface. The value is
updated whenever the debugger regains control from the program.