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1  @
   Executes a command procedure or requests the command interpreter
   to read subsequent command input from a specific file or device.

   Format

     @  filespec [parameter[,...]]
 

2  Parameters
 

filespec

   Specifies either the input device or the file for the preceding
   command, or the command procedure to be executed. The default
   file type is COM. The asterisk (*)  and the percent sign (%)
   wildcard characters are not allowed in the file specification.
 

parameter[,...]

   Specifies from one to eight optional parameters to pass to the
   command procedure. The symbols (P1, P2, . . . P8) are assigned
   character string values in the order of entry. The symbols are
   local to the specified command procedure. Separate each parameter
   with one or more blanks. Use two consecutive quotation marks
   ("")  to specify a null parameter. You can specify a parameter
   with a character string value containing alphanumeric or special
   characters, with the following restrictions:

   o  The command interpreter converts alphabetic characters to
      uppercase and uses blanks to delimit each parameter. To pass a
      parameter that contains embedded blanks or literal lowercase
      letters, place the parameter in quotation marks.

   o  If the first parameter begins with a slash (/),  you must
      enclose the parameter in quotation marks (" ").

   o  To pass a parameter that contains literal quotation marks
      and spaces, enclose the entire string in quotation marks and
      use two consecutive quotation marks within the string. For
      example, the command procedure TEST.COM contains the following
      line:

      $ WRITE SYS$OUTPUT P1

      Enter the following at the DCL prompt ($):

      $ @TEST "Never say ""quit"""

      When the procedure TEST.COM executes, 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, enter the following at the DCL prompt:

      $ @TEST abc"def"ghi

      When the procedure TEST.COM executes, the parameter P1 is
      equated to the following string:

      ABC"def"GHI

   To use a symbol as a parameter, enclose the symbol in single
   quotation marks (' ')  to force symbol substitution. For example:

   $ NAME = "JOHNSON"
   $ @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 INFO.COM.
 

2  Qualifier
 

/OUTPUT

      /OUTPUT=filespec

   Specifies the name of the file to which the command procedure
   output is written. By default, the output is written to the
   current SYS$OUTPUT device. The default output file type is
   .LIS. The asterisk (*)  and the percent sign (%) wildcard
   characters are not allowed in the output file specification.
   System responses and error messages are written to SYS$COMMAND
   as well as to the specified file. The /OUTPUT qualifier must
   immediately follow the file specification of the command
   procedure; otherwise, the qualifier is interpreted as a parameter
   to pass to the command procedure.

   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 will be restored to its
   original equivalence string. This produces the same result
   as using the /OUTPUT qualifier when you execute the command
   procedure.
 

2  Examples

   1.$ CREATE DOFOR.COM
     $ ON WARNING THEN EXIT
     $ IF P1.EQS."" THEN INQUIRE P1 FILE
     $ FORTRAN/LIST 'P1'
     $ LINK 'P1'
     $ RUN 'P1'
     $ PRINT 'P1'
<Ctrl/Z>

     $ @DOFOR AVERAGE

     This example shows a command procedure, named DOFOR.COM, that
     executes the FORTRAN, LINK, and RUN commands to compile,
     link, and execute a program. The ON command requests that
     the procedure not continue if any of the commands result in
     warnings or errors.

     When you execute DOFOR.COM, you can pass the file specification
     of the FORTRAN program as the parameter P1. If you do not
     specify a value for P1 when you execute the procedure, the
     INQUIRE command issues a prompting message to the terminal and
     equates what you enter with the symbol P1. In this example,
     the file name AVERAGE is assigned to P1. The file type is not
     included because the commands FORTRAN, LINK, RUN, and PRINT
     provide default file types.

   2.$ @MASTER/OUTPUT=MASTER.LOG

     This command executes a procedure named MASTER.COM; all output
     is written to the file MASTER.LOG.

   3.$ CREATE FILES.COM
     *.FOR, *.OBJ
<Ctrl/Z>

     $ DIRECTORY @FILES

     This example shows a command procedure, FILES.COM, that
     contains parameters for a DCL command line. You can execute
     this procedure after the DIRECTORY command to get a listing
     of all Fortran source and object files in your current default
     directory.

   4.$ CREATE QUALIFIERS.COM
     /DEBUG/SYMBOL_TABLE/MAP/FULL/CROSS_REFERENCE
<Ctrl/Z>

     $ LINK SYNAPSE@QUALIFIERS

     This example shows a command procedure, QUALIFIERS.COM, that
     contains qualifiers for the LINK command. When you enter the
     LINK command, specify the command procedure immediately after
     the file specification of the file you are linking. Do not type
     a space between the file specification and the @ command.

   5.$ CREATE SUBPROCES.COM
     $ RUN 'P1' -
       /BUFFER_LIMIT=1024 -
       /FILE_LIMIT=4 -
       /PAGE_FILES=256 -
       /QUEUE_LIMIT=2 -
       /SUBPROCESS_LIMIT=2 -
       'P2'  'P3'  'P4'  'P5'  'P6'  'P7'  'P8'
<Ctrl/Z>

     $ @SUBPROCES  LIBRA  /PROCESS_NAME=LIBRA

     This example shows a command procedure named SUBPROCES.COM.
     This procedure issues the RUN command to create a subprocess to
     execute an image and also contains qualifiers defining quotas
     for subprocess creation. The name of the image to be run is
     passed as the parameter P1. Parameters P2 to P8 can be used to
     specify additional qualifiers.

     In this example, the file name LIBRA is equated to P1; it
     is the name of an image to execute in the subprocess. The
     qualifier /PROCESS_NAME=LIBRA is equated to P2; it is an
     additional qualifier for the RUN command.

   6.$ CREATE EDOC.COM
     $ ASSIGN SYS$COMMAND:  SYS$INPUT
     $ NEXT:
     $      INQUIRE NAME "File name"
     $      IF NAME.EQS."" THEN EXIT
     $      EDIT/TPU 'NAME'.DOC
     $      GOTO NEXT
<Ctrl/Z>

     $ @EDOC

     This procedure, named EDOC.COM, invokes the EVE editor. When
     an edit session is terminated, the procedure loops to the
     label NEXT. Each time through the loop, the procedure requests
     another file name for the editor and supplies the default
     file type .DOC. When a null line is entered in response to
     the INQUIRE command, the procedure terminates with the EXIT
     command.

     The ASSIGN command changes the equivalence name of SYS$INPUT
     for the duration of the procedure. This change allows the EVE
     editor to read input data from the terminal, rather than from
     the command procedure file (the default input data stream if
     SYS$INPUT had not been changed). When the command procedure
     exits, SYS$INPUT is reassigned to its original value.
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