HP OpenVMS Systems Documentation

HP OpenVMS DCL Dictionary

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

$ 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.

$ 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).

$ 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.

$ 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.

$ 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.