Unbuffered keyboard input on VAX ADA?

[jehamby@PROBLEM_WITH_INEWS_DOMAIN_FILE (Jake E. Hamby)]

Okay, thanks for all the responses I got.  Basically, everyone used the 
same low-level VMS system calls from packages STARLET and SYSTEM to read 
the input, so the programs all looked pretty much identical.  By the 
way, Ada 9X has the Get_Immediate procedure in TEXT_IO, but of course 
VAX Ada is only Ada 83, so it has to resort to such a kludge. Here is the 
example written by jrg@sema-grenoble.fr:


with SYSTEM;
with TEXT_IO;
with CONDITION_HANDLING;
with STARLET; 
with TASKING_SERVICES;

package body ADS_DIAL_IO is

  function TO_ULW ( X : SYSTEM.ADDRESS ) return SYSTEM.UNSIGNED_LONGWORD
	    renames SYSTEM.TO_UNSIGNED_LONGWORD;

  CLAVIER : STARLET.CHANNEL_TYPE; clavier = keyboard in french
  ITEMLIST: STARLET.ITEM_LIST_TYPE(0..1);


function TRANSLATE_STATUS (STATUS : CONDITION_HANDLING.COND_VALUE_TYPE)
return STRING is
   
  ST_GETMSG  : CONDITION_HANDLING.COND_VALUE_TYPE;
  TEXT_ST    : STRING (1..132);
  TEXT_RET   : STRING (1..80) := ( others => ' ' );
  LG_TEXT_ST : SYSTEM.UNSIGNED_WORD;

begin

  -- translate status => string
  STARLET.GETMSG
     ( STATUS => ST_GETMSG,
       MSGID  => STATUS,
       MSGLEN => LG_TEXT_ST,
       BUFADR => TEXT_ST );

  if CONDITION_HANDLING.SUCCESS (ST_GETMSG) then   

     if INTEGER(LG_TEXT_ST) < TEXT_RET'LENGTH then
      TEXT_RET (1..INTEGER(LG_TEXT_ST)) := TEXT_ST(1..INTEGER(LG_TEXT_ST));
     else
        TEXT_RET := TEXT_ST(1..TEXT_RET'LENGTH);
     end if;

  else

     TEXT_RET (1..32) := "Error in TRANSLATE_STATUS";

  end if;

  return TEXT_RET;

end TRANSLATE_STATUS ;


  function GETKEY return CHARACTER
  is
    STATUS : CONDITION_HANDLING.COND_VALUE_TYPE;
    IOSB   : STARLET.IOSB_TYPE;
    TXT    : STRING ( 1 .. 10 );
    FUNC   : constant := STARLET.IO_READVBLK + STARLET.IO_M_EXTEND ;

  begin
    TASKING_SERVICES.TASK_QIOW
		     ( STATUS => STATUS,
		       CHAN   => CLAVIER,
		       FUNC   => FUNC,
		       IOSB   => IOSB,      
		       P1     => TO_ULW( TXT'address ),
		       P2     => SYSTEM.UNSIGNED_LONGWORD( TXT'length ) ,
		       P5     => TO_ULW( ITEMLIST'address ),
	         P6     => SYSTEM.UNSIGNED_LONGWORD( ITEMLIST'size/8 ) );

    if not CONDITION_HANDLING.SUCCESS ( STATUS ) then
       TEXT_IO.PUT_LINE ("TASK_QIOW: " & TRANSLATE_STATUS( STATUS ) ) ;
    end if ;
    return TXT( 1 );
  end GETKEY;


begin
    STARLET.ASSIGN( STAT,
                    "TT:",
                    CLAVIER ); -- assign channel for keyboard

    -- QIO read initialisation
    ITEMLIST(0).BUF_LEN:= 0;
    ITEMLIST(0).ITEM_CODE:= STARLET.TRM_ESCTRMOVR;
    ITEMLIST(0).BUF_ADDRESS:= SYSTEM.TO_ADDRESS(9);
    ITEMLIST(0).RET_ADDRESS:= SYSTEM.ADDRESS_ZERO; 
    ITEMLIST(1).BUF_LEN:= 0;
    ITEMLIST(1).ITEM_CODE:= STARLET.TRM_MODIFIERS;
    ITEMLIST(1).BUF_ADDRESS:= SYSTEM.TO_ADDRESS(
	    STARLET.TRM_M_TM_ESCAPE +
	    STARLET.TRM_M_TM_NOECHO +
	    STARLET.TRM_M_TM_CVTLOW +
	    STARLET.TRM_M_TM_PURGE  +
	    STARLET.TRM_M_TM_NOFILTR );
    ITEMLIST(1).RET_ADDRESS:= SYSTEM.ADDRESS_ZERO; 

end ADS_DIAL_IO;

--
*	Jake Hamby - "Linux: The Choice of a GNU Generation"		*
*	E-MAIL:  jehamby@lightside.com + jehamby@vms4.sci.csupomona.edu *
* 	http://vms4.sci.csupomona.edu/~jehamby/index.html		*