HP OpenVMS Systems Documentation
HP OpenVMS DCL Dictionary
Assigns, or redirects, a logical queue to a single execution queue. The ASSIGN/QUEUE command can be used only with printer or terminal queues.
ASSIGN/QUEUE queue-name[:] logical-queue-name[:]
The ASSIGN/QUEUE command sets up a one-to-one correspondence between a logical queue and an execution queue. Jobs submitted to the logical queue are always queued to the specified execution queue for eventual printing.
$ INITIALIZE/QUEUE/DEFAULT=FLAG=ONE/START LPA0 $ INITIALIZE/QUEUE TEST_QUEUE $ ASSIGN/QUEUE LPA0 TEST_QUEUE $ START/QUEUE TEST_QUEUE
This example first initializes and starts the printer queue LPA0. The LPA0 queue is set to have a flag page precede each job. The second INITIALIZE/QUEUE command creates the logical queue TEST_QUEUE. The ASSIGN/QUEUE command assigns the logical queue TEST_QUEUE to the printer queue LPA0. The START/QUEUE command starts the logical queue.
$ INITIALIZE/QUEUE/START LPB0
The ASSIGN/QUEUE command is not needed in this example because a logical queue is not being initialized. A printer queue is being initialized; LPB0 is the name of a line printer. After you enter the INITIALIZE/QUEUE/START command, jobs can be queued to LPB0 for printing.
Transfers control from your current process (which then hibernates) to the specified process.
The ATTACH and SPAWN commands cannot be used if your terminal has an associated mailbox.
process-nameSpecifies the name of a parent process or spawned subprocess to which control passes. The process must already exist, be part of your current job, and share the same input stream as your current process. However, the process cannot be your current process or a subprocess created with the /NOWAIT qualifier.
Process names can contain from 1 to 15 alphanumeric characters. If a connection to the specified process cannot be made, an error message is displayed.
The process-name parameter is incompatible with the /IDENTIFICATION qualifier.
The ATTACH command allows you to connect your input stream to another process. You can use the ATTACH command to change control from one subprocess to another subprocess or to the parent process.
When you enter the ATTACH command, the parent or "source" process is put into hibernation, and your input stream is connected to the specified destination process. You can use the ATTACH command to connect to a subprocess that is part of a current job left hibernating as a result of the SPAWN/WAIT command or another ATTACH command as long as the connection is valid. (No connection can be made to the current process, to a process that is not part of the current job, or to a process that does not exist. If any of these connections are attempted, an error message is displayed.)
You can also use the ATTACH command in conjunction with the SPAWN/WAIT command to return to a parent process without terminating the created subprocess. See the description of the SPAWN command for more details.
/IDENTIFICATION=pidSpecifies the process identification (PID) of the process to which terminal control will be transferred. Leading zeros can be omitted. The /IDENTIFICATION qualifier is incompatible with the process-name parameter.
If you omit the /IDENTIFICATION qualifier, you must specify a process name.
$ ATTACH JONES_2
The ATTACH command transfers the terminal's control to the subprocess JONES_2.
The ATTACH command switches control from the current process to a process having the PID 30019. Notice that because the /IDENTIFICATION qualifier is specified, the process-name parameter is omitted.
Invokes the Backup utility (BACKUP) to perform one of the following backup operations:
- Make copies of disk files.
- Save disk files as data in a file created by BACKUP on disk or magnetic tape. (Files created by BACKUP are called save sets.)
- Restore disk files from a BACKUP save set.
- Compare disk files or files in a BACKUP save set with other disk files.
- List information about files in a BACKUP save set to an output device or file.
You cannot invoke BACKUP to back up a system disk; a system disk must be bootstrapped to run.
For more information about BACKUP and backing up the system disk, refer to the HP OpenVMS System Manager's Manual and the HP OpenVMS System Management Utilities Reference Manual or online help.
BACKUP input-specifier output-specifier
Transfers control to a labeled subroutine within a command procedure.
CALL label [parameter [...]]
labelSpecifies a label of 1 to 255 alphanumeric characters that appears as the first item on a command line. A label cannot contain embedded blanks. When the CALL command is executed, control passes to the command following the specified label.
The label can precede or follow the CALL statement in the current command procedure. A label in a command procedure must be terminated with a colon (:). Labels for subroutines must be unique.
Labels declared in inner procedure levels are inaccessible from outer levels, as in the following example:
$CALL B $A: SUBROUTINE $ B: SUBROUTINE $ ENDSUBROUTINE $ENDSUBROUTINE
In this example, the label B in subroutine A is inaccessible from the outer procedure level.
parameter [...]Specifies from one to eight optional parameters to pass to the command procedure. Use quotation marks (" ") to specify a null parameter. The parameters assign character string values to the symbols named P1, P2, and so on in the order of entry, to a maximum of eight. The symbols are local to the specified command procedure. Separate each parameter with one or more spaces.
You can specify a parameter with a character string value containing alphanumeric or special characters, with the following restrictions:
- The command interpreter converts alphabetic characters to uppercase and uses blanks to delimit each parameter. To pass a parameter that contains embedded blanks or lowercase letters, enclose the parameter in quotation marks (" ").
- If the first parameter begins with a slash (/), you must enclose the parameter in quotation marks.
- To pass a parameter that contains quotation marks and spaces, enclose the entire string in quotation marks and use two sets of quotation marks within the string. For example:
$ CALL SUB1 "Never say ""quit"""
When control transfers to SUB1, the parameter P1 is equated to the following string:
Never say "quit"
If a string contains quotation marks and does not contain spaces, the quotation marks are preserved in the string and the letters within the quotation marks remain in lowercase. For example:
$ CALL SUB2 abc"def"ghi
When control transfers to SUB2, the parameter P1 is equated to the string:
To use a symbol as a parameter, enclose the symbol in single quotation marks (` ') to force symbol substitution. For example:
$ NAME = "JOHNSON" $ CALL INFO 'NAME'
The single quotation marks cause the value "JOHNSON" to be substituted for the symbol `NAME'. Therefore, the parameter "JOHNSON" is passed as P1 to the subroutine INFO.
The CALL command transfers control to a labeled subroutine within a command procedure. The CALL command is similar to the @ (execute procedure) command in that it creates a new procedure level. The advantage of the CALL command is that it does not require files to be opened and closed to process the procedure. Using the CALL command also makes managing a set of procedures easier because they can all exist in one file rather than in several files.
When you use the CALL command to transfer control to a subroutine, a new procedure level is created and the symbols P1 to P8 are assigned the values of the supplied arguments. Execution then proceeds until an EXIT command is encountered. At this point, control is transferred to the command line following the CALL command.
Procedures can be nested to a maximum of 32 levels, which includes any combination of command procedure and subroutine calls. Local symbols and labels defined within a nested subroutine structure are treated the same way as if the routines had been invoked with the @ command; that is, labels are valid only for the subroutine level in which they are defined.
Local symbols defined in an outer subroutine level are available to any subroutine levels at an inner nesting level; that is, the local symbols can be read, but they cannot be written to. If you assign a value to a symbol that is local to an outer subroutine level, a new symbol is created at the current subroutine level. However, the symbol in the outer procedure level is not modified.
The SUBROUTINE and ENDSUBROUTINE commands define the beginning and end of a subroutine. The label defining the entry point to the subroutine must appear either immediately before the SUBROUTINE command or on the same command line.
A subroutine can have only one entry point. The subroutine must begin with the SUBROUTINE command as the first executable statement. If an EXIT command is not specified in the procedure, the ENDSUBROUTINE command functions as an EXIT command.
The SUBROUTINE command performs two different functions depending on the context in which it is executed. If executed as the result of a CALL command, it initiates a new procedure level, defines the parameters P1 to P8 as specified in the CALL statement, and begins execution of the subroutine. If the SUBROUTINE verb is encountered in the execution flow of the procedure without having been invoked by a CALL command, all the commands following the SUBROUTINE command are skipped until the corresponding ENDSUBROUTINE command is encountered.
The SUBROUTINE and ENDSUBROUTINE commands cannot be abbreviated to fewer than 4 characters.
/OUTPUT=filespecWrites all output to the file or device specified. By default, the output is written to the current SYS$OUTPUT device and the output file type is .LIS. System responses and error messages are written to SYS$COMMAND as well as to the specified file. If you specify /OUTPUT, the qualifier must immediately follow the CALL command. The asterisk (*) and the percent sign (%) wildcard characters are not allowed in the output file specification.
You can also redefine SYS$OUTPUT to redirect the output from a command procedure. If you place the following command as the first line in a command procedure, output will be directed to the file you specify:
$ DEFINE SYS$OUTPUT filespec
When the procedure exits, SYS$OUTPUT is restored to its original equivalence string. This produces the same result as using the /OUTPUT qualifier when you execute the command procedure.
$ $! CALL.COM $ $! Define subroutine SUB1 $! $ SUB1: SUBROUTINE . . . $ CALL SUB2 !Invoke SUB2 from within SUB1 . . . $ @FILE !Invoke another procedure command file . . . $ EXIT $ ENDSUBROUTINE !End of SUB1 definition $! $! Define subroutine SUB2 $! $ SUB2: SUBROUTINE . . . $ EXIT $ ENDSUBROUTINE !End of SUB2 definition $! $! Start of main routine. At this point, both SUB1 and SUB2 $! have been defined but none of the previous commands have $! been executed. $! $ START: $ CALL/OUTPUT=NAMES.LOG SUB1 "THIS IS P1" . . . $ CALL SUB2 "THIS IS P1" "THIS IS P2" . . . $ EXIT !Exit this command procedure file
The command procedure in this example shows how to use the CALL command to transfer control to labeled subroutines. The example also shows that you can call a subroutine or another command file from within a subroutine.
The CALL command invokes the subroutine SUB1, directing output to the file NAMES.LOG and allowing other users write (W) access to the file. The subroutine SUB2 is called from within SUB1. The procedure executes SUB2 and then uses the @ (execute procedure) command to invoke the command procedure FILE.COM.
When all the commands in SUB1 have executed, the CALL command in the main procedure calls SUB2 a second time. The procedure continues until SUB2 has executed.
Cancels wakeup requests for a specified process, including wakeup requests scheduled with either the RUN command or the $SCHDWK system service.
Requires one of the following:
- Ownership of the process
- GROUP privilege to cancel scheduled wakeup requests for processes in the same group but not owned by you
- WORLD privilege to cancel scheduled wakeup requests for any process in the system
node-name::The name of the node on which the specified process is running.
You cannot specify a node name on a different OpenVMS Cluster system from the current process.
process-nameThe name of the process for which wakeup requests are to be canceled. The process name can have up to 15 alphanumeric characters.
The specified process must be in the same group as the current process.
The CANCEL command cancels scheduled wakeup requests for the specified process.
The CANCEL command does not delete the specified process. If the process is executing an image when the CANCEL command is issued for it, the process hibernates instead of exiting after the image completes execution.
To delete a hibernating process for which wakeup requests have been canceled, use the STOP command. You can determine whether a subprocess has been deleted by entering the SHOW PROCESS command with the /SUBPROCESSES qualifier.
A local process name can look like a remote process name. Therefore, if you specify ATHENS::SMITH, the system checks for a process named ATHENS::SMITH on the local node before checking node ATHENS for a process named SMITH.
You also can use the /IDENTIFICATION=pid qualifier to specify a process name. If you use the /IDENTIFICATION qualifier and the process-name parameter together, the qualifier overrides the parameter. If you do not specify either the process-name parameter or the /IDENTIFICATION qualifier, the CANCEL command cancels scheduled wakeup requests for the current (that is, the issuing) process.
/IDENTIFICATION=pidIdentifies the process by its process identification (PID). You can omit leading zeros when you specify the PID.
$ CANCEL CALENDAR
The CANCEL command in this example cancels a wakeup request for a process named CALENDAR (which continues to hibernate until it is deleted with the STOP command).
$ RUN/SCHEDULE=14:00 STATUS %RUN-S-PROC_ID, identification of created process is 0013012A . . . $ CANCEL/IDENTIFICATION=13012A
The RUN command in this example creates a process to execute the image STATUS. The process hibernates and is scheduled to be awakened at 14:00. Before the process is awakened, the CANCEL command cancels the wakeup request.
$ RUN/PROCESS_NAME=LIBRA/INTERVAL=1:00 LIBRA %RUN-S-PROC_ID, identification of created process is 00130027 . . . $ CANCEL LIBRA $ STOP LIBRA
The RUN command in this example creates a subprocess named LIBRA to execute the image LIBRA.EXE at hourly intervals.
Subsequently, the CANCEL command cancels the wakeup request. The process continues to exist, but in a state of hibernation, until the STOP command deletes it.
Closes a file opened with the OPEN command and deassigns the associated logical name.
logical-name[:]Specifies the logical name assigned to the file when it was opened with the OPEN command.
Files that are opened for reading or writing at the command level remain open until closed with the CLOSE command, or until the process terminates. If a command procedure that opens a file terminates without closing the open file, the file remains open; the command interpreter does not automatically close it.
/DISPOSITION=optionSpecifies what action to take when the file is closed. The options are:
DELETE Delete the file. KEEP (default) Keep the file. Print the file. SUBMIT Submit the file.
/ERROR=labelSpecifies a label in the command procedure to receive control if the close operation results in an error. Overrides any ON condition action specified. If an error occurs and the target label is successfully given control, the global symbol $STATUS retains the code for the error that caused the error path to be taken.
/NOLOGGenerates a warning message when you attempt to close a file that was not opened by DCL. If you specify the /ERROR qualifier, the /LOG qualifier has no effect. If the file has not been opened by DCL, the error branch is taken and no message is displayed.
$ OPEN/READ INPUT_FILE TEST.DAT $ READ_LOOP: $ READ/END_OF_FILE=NO_MORE INPUT_FILE DATA_LINE . . . $ GOTO READ_LOOP $ NO_MORE: $ CLOSE INPUT_FILE
The OPEN command in this example opens the file TEST.DAT and assigns it the logical name of INPUT_FILE. The /END_OF_FILE qualifier on the READ command requests that, when the end-of-file (EOF) is reached, the command interpreter should transfer control to the line at the label NO_MORE. The CLOSE command closes the input file.
$ @READFILE [Ctrl/Y] $ STOP $ SHOW LOGICAL/PROCESS . . . "INFILE" = "_DB1" "OUTFILE" = "_DB1" $ CLOSE INFILE $ CLOSE OUTFILE
In this example, pressing Ctrl/Y interrupts the execution of the command procedure READFILE.COM. Then, the STOP command stops the procedure. The SHOW LOGICAL/PROCESS command displays the names that currently exist in the process logical name table. Among the names listed are the logical names INFILE and OUTFILE, assigned by OPEN commands in the procedure READFILE.COM.
The CLOSE commands close these files and deassign the logical names.