Re: How to pass commandline parameters to a vax vms ada main prog

[Peter Amey <pna@erlang.praxis.co.uk>]

On Thu, 23 Jan 1997, Markus Wolfgart wrote:

> I'm running in a programing problem and can't find a satisfactory
> solution, please help if you know the right anwser.
> 
> How to pass comandline parameters to an ada main procedure written
> in vax vms 5.1 ada. Do I need to import the starlet lib ?
> 
> thanks for help in advance.
> 
> markus
> 

Useful fragments follow:

  LenCmdLine                  : constant INTEGER := 255;

  subtype TypCmdLineRange     is INTEGER range 1..LenCmdLine;
  subtype TypCmdLine          is STRING (TypCmdLineRange);



with STARLET;
....
  procedure ReadCmdLine( CmdLineFound : out BOOLEAN;
                         CmdLine      : out TypCmdLine;
                         CmdLinePntr  : out TypCmdLineRange )
  --# derives CmdLine      from CmdLine &
  --#         CmdLinePntr  from &
  --#         CmdLinefound from;
  is
  --# hide ReadCmdLine
  -- FUNCTION :
  --
  -- Checks if command line supplied, if supplied sets 'CmdLineFound' 
True, else
  -- sets it False. Reads any supplied command line into the array 
'CmdLine' and
  -- sets 'CmdLinePntr' to initial value of 1.
  --
  -- The command line string returned in 'CmdLine' does not include the 
program name.
  --
  -- OPERATION :
  --
  -- Uses VAX/VMS run time library procedure Lib$Get_Foreign ( which is 
documented in
  -- the VAX/VMS Runtime Library manual Volume 8B )

    Status     : COND_VALUE_TYPE;
    Found      : BOOLEAN;
    CmdLineLen : UNSIGNED_WORD;
    StsValue   : INTEGER;
    PrmptFlag  : INTEGER;

    procedure GetForeign( Status    : out COND_VALUE_TYPE;
                          CmdString : out STRING;
                          Prompt    : in  STRING := STRING'NULL_PARAMETER;
                          OutLen    : out UNSIGNED_WORD;
                          Force     : in  INTEGER );

    pragma interface( VAXRTL, GetForeign );
    pragma import_valued_procedure( GetForeign, "LIB$Get_Foreign" );

    --  This declaration is mapped to the VAX/VMS RTL function 
LIB$Get_Foreign.
    --  It reads the programs invoking command line ( if any ) and 
returns it
    --  in 'CmdString' and the number of characters it contains in 'OutLen'.
    --  If 'Force' is set to 1 it prompts with string 'Prompt' if no 
command line
    --  is supplied. It does not prompt if 'Force' is set to 0. The returned
    --  command line does not include the program name. Success of 
operation is
    --  returned in the function result and should be SS_Normal if 
successful.

  begin
    for Index in TypCmdLineRange loop 
        CmdLine( Index ) := ' '; 
    end loop;

    PrmptFlag := 0;                -- no Prompt if command line is not found
    CmdLineLen := 0;

    GetForeign( Status, CmdLine, STRING'NULL_PARAMETER, CmdLineLen, 
PrmptFlag );

    Found := ( CmdLineLen > 0 ) and ( Status = STARLET.SS_Normal );  -- 
SS$_Normal implies
                                                                 -- a 
successful exit
    CmdLinePntr := 1;

    if not Found then
       for Index in TypCmdLineRange loop 
           CmdLine( Index ) := ' ';  
       end loop;
    end if;
    CmdLineFound := Found;

  end ReadCmdLine;

  
----------------------------------------------------------------------------

Sorry about some of the lie wraps in the above!

regards Peter