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example of smg$read_string?

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The Question is:

 
how do I setup the terminator-set argument for smg$read_string in C.
I am trying to define up/down arrow keys as terminators for a string input.
 
 

The Answer is :

/*
//  SMG$READ_STRING.C
//
//  Demonstration of using SMG$READ_STRING.C, dynamic string
//  descriptors, various other SMG and OpenVMS calls.
//
//  Stephen Hoffman, Compaq Computer Corporation
//    Based on various other examples of SMG$READ_STRING found
//    around, updated to DEC C, various updates and changes made.
//
//  To build:
//    $ cc/decc/prefix=all SMG$READ_STRING
//    $ link SMG$READ_STRING
//
*/
 
#include <descrip.h>
#include <lib$routines.h>
#include <smgdef.h>
#include <smg$routines.h>
#include <ssdef.h>
#include <stdio.h>
#include <stdlib.h>
#include <stsdef.h>
#include <unistd.h>
 
struct TerminatorSetLongForm
  {
  unsigned short int MaskSize;
  unsigned short int NotUsed;
  void *MaskAddr;
  } TrmByRef;
 
struct TerminatorSetShortForm
  {
  unsigned short int MaskSize;
  unsigned short int NotUsed;
  long  BitMask;
  } TrmByVal;
 
main()
  {
  int RetStat;
  int DispRows = 22, DispCols = 78, PasteRow = 2, PasteCol = 2;
  unsigned int NewPBId, DispId, KeybId;
  unsigned short int Message1Len, Message2Len, DDLen = 80;
  unsigned long int BitMask;
  struct dsc$descriptor_d Message1Dsc =
    { 0, DSC$K_DTYPE_T, DSC$K_CLASS_S, NULL };
  struct dsc$descriptor_d Message2Dsc =
    { 0, DSC$K_DTYPE_T, DSC$K_CLASS_S, NULL };
  $DESCRIPTOR(Prompt1Dsc, "Enter string terminated by ^A: ");
  $DESCRIPTOR(Prompt2Dsc, "Enter string terminated by ^B: ");
 
  printf("\n");
  printf("SMG$READ_STRING demonstration program\n");
  printf("\n");
  printf("You must issue SET TERMINAL/NOLINE_EDITING before\n");
  printf("attempting to use this program, otherwise the program\n");
  printf("will not be able to receive and process the required\n");
  printf("control characters.\n");
  printf("\n");
  printf("SMG$READ_STRING is now pausing briefly...\n");
  sleep( 5 );
  printf("Now continuing execution...\n");
 
  RetStat = lib$sget1_dd( &DDLen, &Message1Dsc );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
  RetStat = lib$sget1_dd( &DDLen, &Message2Dsc );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  /*
  // Set up long form terminator
  // ^A (bit 1) is the terminator
  */
  TrmByRef.MaskSize = 4;
  TrmByRef.NotUsed  = 0;
  TrmByRef.MaskAddr = &BitMask;
  BitMask           = 1L<<1;
 
  /*
  // Set up short form terminator.
  // ^B (bit 2) is the terminator.
  */
  TrmByVal.MaskSize = 0;
  TrmByVal.NotUsed  = 0;
  TrmByVal.BitMask  = 1L<<2;
 
  /*
  // establish terminal screen as pasteboard
  */
  RetStat = SMG$CREATE_PASTEBOARD(&NewPBId, 0,0,0,0);
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  /*
  // establish a virtual keyboard
  */
  RetStat = SMG$CREATE_VIRTUAL_KEYBOARD(&KeybId);
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  /*
  // establish a virtual display region
  */
  RetStat = SMG$CREATE_VIRTUAL_DISPLAY(&DispRows, &DispCols, &DispId, 0,0,0);
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  /*
  // paste virtual display to pasteboard at row 1, col 1
  */
  RetStat = SMG$PASTE_VIRTUAL_DISPLAY(&DispId, &NewPBId, &PasteRow, &PasteCol);
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  /*
  // Do what we came here to do...
  */
  RetStat = SMG$READ_STRING(&KeybId, &Message1Dsc,
    &Prompt1Dsc,0,0,0,&TrmByRef,&Message1Len,0,0,0,0,0,0);
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  PasteRow += 2;
  RetStat = SMG$SET_CURSOR_ABS( &DispId, &PasteRow, &PasteCol );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  RetStat = SMG$PUT_LINE( &DispId, &Message1Dsc, 0,0,0,0,0,0 );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  PasteRow += 2;
  RetStat = SMG$SET_CURSOR_ABS( &DispId, &PasteRow, &PasteCol );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  RetStat = SMG$READ_STRING(&KeybId, &Message2Dsc,
    &Prompt2Dsc,0,0,0,&TrmByVal,&Message2Len,0,0, 0,0,0,0);
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  PasteRow += 2;
  RetStat = SMG$SET_CURSOR_ABS( &DispId, &PasteRow, &PasteCol );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  RetStat = SMG$PUT_LINE( &DispId, &Message2Dsc, 0,0,0,0,0,0 );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  sleep( 1 );
 
  /*
  //  Free up the dynamic string descriptors before exiting.
  */
  RetStat = lib$sfree1_dd( &Message1Dsc );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
  RetStat = lib$sfree1_dd( &Message2Dsc );
  if (!$VMS_STATUS_SUCCESS( RetStat ))
    return RetStat;
 
  return SS$_NORMAL;
  }

  

     

     
answer written or last revised on ( 10-DEC-1998 )
     
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