DBG$HELP.HLB  —  DEBUG  SPAWN
    Creates a subprocess, enabling you to execute DCL commands
    without terminating a debugging session or losing your debugging
    context.

                                   NOTE

       This command is not available in the VSI DECwindows Motif for
       OpenVMS user interface to the debugger.

    Format

      SPAWN  [DCL-command]

1  –  Parameters 

 DCL-command

    Specifies a DCL command which is then executed in a subprocess.
    Control is returned to the debugging session when the DCL command
    terminates.

    If you do not specify a DCL command, a subprocess is created
    and you can then enter DCL commands. Either logging out of the
    spawned process or attaching to the parent process (with the DCL
    command ATTACH) returns you to your debugging session.

    If the DCL command contains a semicolon, you must enclose the
    command in quotation marks (").  Otherwise the semicolon is
    interpreted as a debugger command separator. To include a
    quotation mark in the string, enter two consecutive quotation
    marks ("").

2  –  Qualifiers

2.1    /INPUT 

       /INPUT=file-spec

    Specifies an input DCL command procedure containing one or more
    DCL commands to be executed by the spawned subprocess. The
    default file type is .COM. If you specify a DCL command string
    with the SPAWN command and an input file with /INPUT, the command
    string is processed before the input file. After processing
    of the input file is complete, the subprocess is terminated.
    Do not use the asterisk (*)  wildcard character in the file
    specification.

2.2    /OUTPUT 

       /OUTPUT=file-spec

    Writes the output from the SPAWN operation to the specified
    file. The default file type is .LOG. Do not use the asterisk
    (*)  wildcard character in the file specification.

2.3    /WAIT 

       /WAIT (default)
       /NOWAIT

    Controls whether the debugging session (the parent process) is
    suspended while the subprocess is running. The /WAIT qualifier
    (default) suspends the debugging session until the subprocess
    is terminated. You cannot enter debugger commands until control
    returns to the parent process.

    The /NOWAIT qualifier executes the subprocess in parallel with
    the debugging session. You can enter debugger commands while the
    subprocess is running. If you use /NOWAIT, you should specify
    a DCL command with the SPAWN command; the DCL command is then
    executed in the subprocess. A message indicates when the spawned
    subprocess completes.

    The kept debugger (that is, the debugger invoked with the DCL
    command DEBUG/KEEP) shares I/O channels with the parent process
    when it is run by a SPAWN/NOWAIT command. Therefore, in the VSI
    DECwindows Motif for OpenVMS user interface, you must press the
    Return key twice on the DECterm from which the debugger was run
    after the debugger version number has appeared in the command
    view.

    Optionally, you can execute the kept debugger in the following
    manner:

     $ DEFINE DBG$INPUT NL:
     $ SPAWN/NOWAIT RUN DEBUG/KEEP

3  –  Description 

    The SPAWN command acts exactly like the DCL command SPAWN. You
    can edit files, compile programs, read mail, and so on without
    ending your debugging session or losing your current debugging
    context.

    In addition, you can spawn a DCL command SPAWN. DCL processes the
    second SPAWN command, including any qualifier specified with that
    command.

    Related command:

       ATTACH

4  –  Examples 

    1.DBG> SPAWN
      $

      This example shows that the SPAWN command, without a parameter,
      creates a subprocess at DCL level. You can now enter DCL
      commands. Log out to return to the debugger prompt.

    2.DBG> SPAWN/NOWAIT/INPUT=READ_NOTES/OUTPUT=0428NOTES

      This command creates a subprocess that is executed in parallel
      with the debugging session. This subprocess executes the DCL
      command procedure READ_NOTES.COM. The output from the spawned
      operation is written to the file 0428NOTES.LOG.

    3.DBG> SPAWN/NOWAIT SPAWN/OUT=MYCOM.LOG @MYCOM

      This command creates a subprocess that is executed in parallel
      with the debugging session. This subprocess creates another
      subprocess to execute the DCL command procedure MYCOM.COM. The
      output from that operation is written to the file MYCOM.LOG.
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