HP OpenVMS DCL Dictionary
SET VERIFY
Controls whether command lines and data lines in command procedures are
displayed at the terminal or are printed in a batch job log. The
information displayed by the SET VERIFY command can help you in
debugging command procedures.
Format
SET VERIFY [=([NO]PROCEDURE, [NO]IMAGE)]
SET NOVERIFY
Parameter
([NO]PROCEDURE, [NO]IMAGE)
Specifies one or both types of verification. Procedure verification
causes each DCL command line in a command procedure to be written to
the output device. Image verification causes data lines (input data
that is included as part of the SYS$INPUT input stream) to be written
to the output device.
By default, both types of verification are set or cleared with SET
VERIFY and SET NOVERIFY. If you specify only one keyword, the other is
not affected. If you specify only one keyword, omit the parentheses.
Description
By default, the SET VERIFY and SET NOVERIFY commands set or clear both
types of verification. The default setting for command procedures
executed interactively is SET NOVERIFY. System responses and error
messages are, however, always displayed. The default for batch jobs is
SET VERIFY.
If you use the SET VERIFY command to override the default setting, the
system displays each command and data line in the command procedure as
it reads it. When verification is in effect, the command interpreter
displays each command line after it has completed initial scanning and
before the command is parsed and executed. You see the results of
symbol substitution performed during scanning, but not the results of
symbol substitution performed during parsing and evaluation.
When you change the verification setting, the new setting remains in
effect for all command procedures that you subsequently execute.
A file must have read (R) access to allow the SET VERIFY command to set
verification.
Examples
| #1 |
$ SET VERIFY = PROCEDURE
|
In this example, procedure verification is turned on. If image
verification was on, it remains on; if image verification was off, it
remains off.
| #2 |
$ SET VERIFY
$ INDEX == "$INDEX.EXE"
$ CONTENTS == "$CONTENTS.EXE"
$ TABLE == "$TABLE.EXE"
$ SET NOVERIFY
$ EXIT
|
Procedure and image verification are turned on at the beginning of the
command procedure so that the system displays all the command and data
lines in the procedure as it reads them. At the end of the procedure,
the SET NOVERIFY command restores the system default (no procedure or
image verification).
| #3 |
$ PROC_VER = F$ENVIRONMENT("VERIFY_PROCEDURE")
$ IMAGE_VER = F$ENVIRONMENT("VERIFY_IMAGE")
$ HOLD_PREFIX = F$ENVIRONMENT("VERIFY_PREFIX")
$ SET PREFIX "(!%T)"
$ SET VERIFY
.
.
.
$ TEMP = F$VERIFY(PROC_VER, IMAGE_VER)
$ SET PREFIX "''HOLD_PREFIX'"
|
This command procedure uses the F$ENVIRONMENT lexical function to save
the current procedure and image verification setting, as well as the
current verification prefix string. The SET PREFIX command sets the
verification prefix to be used in the current command procedure. It
uses an FAO control string to produce the time each command is read by
the command interpreter (DCL), surrounded by parentheses. Then the SET
VERIFY command turns on both procedure and image verification.
Subsequently, the F$VERIFY lexical function is used to restore the
original verification settings. The SET PREFIX command returns the
verification prefix to its previous setting. Note how the symbol
HOLD_PREFIX is used in the SET PREFIX command. This preserves casing
and special characters in the stored string.
| #4 |
$ SET VERIFY
$ @TEST
$ RUN AVERAGE
1
2
3
$ EXIT
|
In this example, the SET VERIFY command turns procedure and image
verification on. When the command procedure TEST.COM is executed
interactively, the command lines and the data lines for the program
AVERAGE are displayed on the terminal. The data lines were entered in
the command procedure on lines that did not begin with the DCL prompt.
| #5 |
$ SET VERIFY
$ COUNT = 1
$ IF P'COUNT' .NES. "" THEN GOTO &P'COUNT'
.
.
.
$ EXIT
|
When this command procedure is executed interactively, the SET VERIFY
command causes the command and data lines to be displayed. Symbols that
are substituted during the first phase of symbol substitution (such as
'COUNT') are displayed by the SET VERIFY command, but other symbols are
not. The following lines are displayed when this procedure is executed
interactively:
$ COUNT = 1
$ IF P1 .NES. "" THEN GOTO &P1
.
.
.
|
Although these values are not displayed, the value for P1 is
substituted during the third phase of symbol substitution, and the
value for &P1 is substituted during the second phase.
| 
