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1  SPAWN
   Creates a subprocess of the current process. Portions of the
   current process context are copied to the subprocess.

   The RESOURCE_WAIT state is required to spawn a process.
   Requires TMPMBX (temporary mailbox) or PRMMBX (permanent
   mailbox) privilege. The SPAWN command does not manage terminal
   characteristics. The SPAWN and ATTACH commands cannot be used if
   your terminal has an associated mailbox.

   Format

     SPAWN  [command-string]
 

2  Parameter
 

command-string

   Specifies a command string of less than 132 characters that is
   to be executed in the context of the created subprocess. When
   the command completes execution, the subprocess terminates and
   control returns to the parent process. If both a command string
   and the /INPUT qualifier are specified, the specified command
   string executes before additional commands are obtained from the
   /INPUT qualifier.
 

2  Qualifiers
 

/CARRIAGE_CONTROL

      /CARRIAGE_CONTROL
      /NOCARRIAGE_CONTROL

   Determines whether carriage-return and line-feed characters are
   prefixed to the subprocess's prompt string. By default, SPAWN
   copies the current setting of the parent process.
 

/CLI

      /CLI=cli-filespec
      /NOCLI

   Specifies the name of a command language interpreter (CLI) to
   be used by the subprocess. The default CLI is the same as the
   parent process (defined in SYSUAF). If you specify the /CLI
   qualifier, the attributes of the parent process are copied to
   the subprocess.

   The CLI you specify must be located in SYS$SYSTEM and have the
   file type EXE.
 

/INPUT

      /INPUT=filespec

   Specifies an input file containing one or more DCL commands to
   be executed by the spawned subprocess. The file type defaults
   to .COM. The asterisk (*)  and the percent sign (%) wildcard
   characters are not allowed in the file specification. Once
   processing of the input file is complete, the subprocess is
   terminated. If both a command string and the /INPUT qualifier
   are specified, the specified command string executes before
   additional commands are obtained from the /INPUT qualifier.
   If neither is specified, SYS$INPUT is assumed (in which case a
   SPAWN/NOWAIT command is aborted if Ctrl/Y is pressed to abort
   something running in your parent process).

   You cannot explicitly specify non-record-oriented, process-
   permanent files (NRO PPFs) with the /INPUT qualifier. The system
   displays an error message when it encounters such a file as the
   value for the /INPUT qualifier.

   Note that when NRO PPFs are used as implicit input (that is, the
   /INPUT qualifier is not specified and SYS$INPUT is a NRO PPF),
   the SPAWN command can succeed, as shown in the following table:

   Process Type     SYS$INPUT  Implicit Input

   Interactive      NRO PPF    SYS$COMMAND

   Noninteractive   NRO PPF    Null device

   Any              Any other  SYS$INPUT

   If SYS$INPUT is a terminal, it cannot have an associated terminal
   mailbox.
 

/KEYPAD

      /KEYPAD (default)
      /NOKEYPAD

   Copies keypad key definitions and the current keypad state from
   the parent process. By default, if you have established key
   definitions or states with the DEFINE/KEY or the SET KEY command,
   these settings are copied to the subprocess. Use the /NOKEYPAD
   qualifier if you do not want the key settings to be copied.
 

/LOG

      /LOG (default)
      /NOLOG

   Displays the assigned subprocess name and any messages indicating
   transfer of control between processes.
 

/LOGICAL_NAMES

      /LOGICAL_NAMES (default)
      /NOLOGICAL_NAMES

   Copies process logical names and logical name tables to the
   subprocess. By default, all process logical names and logical
   name tables are copied to the subprocess except those explicitly
   marked CONFINE or created in executive or kernel mode.
 

/NOTIFY

      /NOTIFY
      /NONOTIFY (default)

   Controls whether a message is broadcast to your terminal
   notifying you that your subprocess has completed or aborted.
   This qualifier should not be used unless you specify the /NOWAIT
   qualifier. The /NOTIFY qualifier cannot be specified when the
   SPAWN command is executed from within a noninteractive process.

   Note that messages broadcast as a result of using the /NOTIFY
   qualifier are considered to be DCL messages. Therefore, if SET
   BROADCAST=NODCL is in effect, all such notification messages are
   suppressed.
 

/OUTPUT

      /OUTPUT=filespec

   Specifies the output file to which the results of the SPAWN
   operation are written. The asterisk (*)  and the percent sign (%)
   wildcard characters cannot be used in the file specification.
   (Do not specify SYS$COMMAND as a file specification for the
   /OUTPUT qualifier when using the /NOWAIT qualifier; both parent
   and subprocess output will be displayed simultaneously on your
   terminal.)

                                CAUTION

      If you include a version number in the filespec argument
      of the /OUTPUT qualifier, and that version of the specified
      file already exists, the existing file is replaced with the
      new output.

   You cannot explicitly specify non-record-oriented, process-
   permanent files (NRO PPFs) with the /OUTPUT qualifier. The system
   displays an error message when it encounters such a file as the
   value for the /OUTPUT qualifier.

   Note that when NRO PPFs are used as implicit output, the SPAWN
   command can succeed, as shown in the following table:

   Process
   Type         SYS$OUTPUT   Implicit Output

   Any          NRO PPF      Mailbox transmitting records for parent
                             to write to its current SYS$OUTPUT
                             device

   Any          Any other    SYS$OUTPUT

   If you omit the /OUTPUT qualifier, output is written to the
   current SYS$OUTPUT device.
 

/PRIVILEGES

      /PRIVILEGES={CURRENT|AUTHORIZED}

   Determines whether the spawned process inherits the current
   process' current or authorized privileges as its authorized
   privileges. By default, the authorized privilege mask for
   the subprocess is taken from the current privileges of its
   creator. (This corresponds to /PRIVILEGES=CURRENT.) If the
   /PRIVILEGES=AUTHORIZED qualifier is specified, the subprocess'
   authorized privileges will be taken from the caller's authorized
   privileges.
 

/PROCESS

      /PROCESS=subprocess-name

   Specifies the name of the subprocess to be created. If you omit
   the /PROCESS qualifier, a unique process name is assigned with
   the same base name as the parent process and a unique number. The
   default subprocess name format is username_n. If you specify a
   process name that already exists, an error message is displayed.
   If the /LOG qualifier has been specified, the assigned name of
   the subprocess is displayed.
 

/PROMPT

      /PROMPT[=string]

   Specifies the prompt string for DCL to use in the subprocess. The
   default is the prompt of the parent process.

   The string can consist of more than one character. All valid
   ASCII characters can be used in the string. The string must be
   enclosed in quotation marks (" ")  if it contains spaces, special
   characters, or lowercase characters. Otherwise, letters are
   automatically converted to uppercase, and leading and trailing
   spaces are removed.

   If no string is specified, the dollars sign ($)  DCL default
   prompt string is used for the subprocess.
 

/SYMBOLS

      /SYMBOLS (default)
      /NOSYMBOLS

   Determines whether global and local symbols (except $RESTART,
   $SEVERITY, and $STATUS) are passed to the subprocess. $RESTART,
   $SEVERITY, and $STATUS symbols are never passed to the
   subprocess.
 

/TABLE

      /TABLE=command-table

   Specifies the name of an alternate command table to be used by
   the subprocess.
 

/TRUSTED

      /TRUSTED
      /NOTRUSTED

   Indicates that the SPAWN command input originates in a trusted
   command procedure. SPAWN commands are not allowed in CAPTIVE
   accounts. The /TRUSTED qualifier provides a way for properly
   written captive command procedures to perform SPAWN operations
   when the command input originates in the captive command
   procedure where it can be trusted. For more information about
   trusted command procedures, see the OpenVMS Guide to System
   Security.
 

/WAIT

      /WAIT (default)
      /NOWAIT

   Requires that you wait for the subprocess to terminate before
   you enter another DCL command. The /NOWAIT qualifier allows
   you to enter new commands while the subprocess is running.
   (Use the /OUTPUT qualifier with the /NOWAIT qualifier to avoid
   displaying both parent and subprocess output on the terminal
   simultaneously.)

   Note that specifying the /NOWAIT qualifier causes both input and
   output to be shared with the parent process. If the input device
   is a terminal, control characters, such as Ctrl/T or Ctrl/Y,
   also affect all subprocesses sharing the input device. The Ctrl/Y
   control character, for example, interrupts all such subprocesses.

   This problem may be avoided by specifying /INPUT=NL:.
 

2  Example

 $ RUN MYPROG
       .
       .
       .

 $ <Ctrl/Y>
 $ SPAWN MAIL
 %DCL-S-SPAWNED, process SMITH_1 spawned
 %DCL-S-ATTACHED, terminal now attached to process SMITH_1
 MAIL> READ
    .
    .
    .
 MAIL> EXIT
 %DCL-S-RETURNED, control returned to process SMITH
 $ CONTINUE

     The SPAWN command in this example allows you to enter the
     OpenVMS Mail utility (MAIL) without terminating the currently
     running program. After you exit from Mail, control is returned
     to the parent process.
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