getch.vms.txt

this is a mirrored site c-faq. thought might need offline

Newsgroups: comp.lang.c
From: [e-mail] (Andreas Fassl)
Subject: Re: How to write PRESS ANY KEY routine
Message-ID: <[e-mail]>
References: <[e-mail]> <[e-mail]>
Date: Fri, 4 Feb 1994 10:22:09 GMT

In <[e-mail]> [e-mail] (Dan Pop) writes:
>In <[e-mail]> <[e-mail]> writes:
>> I need help in writing a routine which will detect a press of a key on the
>>keyboard without the need to press enter afterwards. I know that there exist
>>functions to do that but as far as I know, they are not portable to other
>>systems such as UNIX or VMS. Are there any standard functions that would do
>>
>Forget about writing your own portable routine to do that. It cannot be
>done. You have to resort to system specific calls, which are beyond the
>scope of comp.lang.c.

Hm,

don't hit me, I found this in my archive, maybe something for the FAQ, too.

-andreas


From comp.os.vms Tue May 19 14:44:09 1992

In a previous article, [e-mail] (David Hardy) wrote:
>In message <[e-mail]>, Yang ([e-mail]) writes:
> 
>> Hi,
>>
>> One simple question I cannot make it out:  Is there any command in VAX C
>> act as getch() in the Micro-soft C?  That is, without hit the <RETURN> the
>> program can directly pass the value of key strok to the viarble.
>>
>> Any respond will be appreciated.  Thanks.
> 
>It is possible by using the Screen Management Routines (SMG). A sample program
>is included below by 'signature' and the function you'll be interested in is
>GETKEY. You'll need to ensure that smgdef and ssdef are #include'd for the

                [*** stuff deleted ***]


   A simpler method would be to just include the following header file which
redefines putchar() and defines getkey().

/*
    TERMIO.H fixes a few anomolies of the VAX C runtime library.

    Version 1.6 10-APR-92      Anthony C. McCracken

    getkey() returns the next keystroke without echo or a carriage
             return.

    putchar(char) works like the UNIX putchar, buffering the characters
                  until the buffer fills up (512 chars) or a newline
                  character is putchared.

    To use these routines, just include this header file after all the
    other #include statements.

*/

#include <ssdef.h>
#include <iodef.h>

typedef struct {
           short int status;              /* I/O completion status */
           short int bcount;              /* byte transfer count   */
           int dev_dep_data;              /* device dependant data */
        } iosb;                  /* This is a QIO I/O Status Block */

typedef struct {
           short int length;              /* Length of string      */
           char      dtype;               /* Type 14 is a string   */
           char      class;               /* Class 1 is fixed length */
           char      *ptr;                /* Pointer to the string */
        } descr;                 /* once initialized, this is a fixed */
                                 /* length string descriptor */

short int __tty_chan = 0;

void build_descr(descr *p,char *s)    /* Builds a fixed length string */
                                      /* descriptor                   */
{

   p->length = strlen(s);
   p->dtype = 14;
   p->class = 1;
   p->ptr = s;
}

char getkey()
{
   descr __tty_name;
   char __tty_buff;
   iosb __tty_iosb;
   int __i;

   if (__tty_chan == 0) {
      build_descr(&__tty_name,"TT:");
      if (sys$assign(&__tty_name,&__tty_chan,0,0) != SS$_NORMAL) return(0);
   }
   __i = sys$qiow(0,__tty_chan,IO$_READVBLK+IO$M_NOECHO,&__tty_iosb,0,0,
                &__tty_buff,1,0,0,0,0);
   if (__i != SS$_NORMAL) return(0);
   else return(__tty_buff);
}

#define __putcharbufsize 512
char __putcbuff[__putcharbufsize];
int __pcp = 0;

#define putchar(c) {if(c=='\n') __barfout(__putcbuff,&__pcp); \
                   else __putcbuff[__pcp++]=c; \
                   if (__pcp>__putcharbufsize-2) __barfout(__putcbuff,&__pcp);}

void __barfout(char *s, int *__i)
{
   s[(*__i)++] = '\n';
   s[*__i] = 0;
   fputs(s,stdout);
   *__i = 0;
}



Example:

#include <stdio.h>
#include "TERMIO.H"
main()
{
   char c;

   printf("Press ANY key to continue\n");
   c = getkey();
   printf("You pressed the %c key\n",c);
}


+----------------------------------------+-----------------------------------+
| Anthony C. McCracken                   |                                   |
| Northern Arizona University            | Boom boom boom,,, Still going !   |
| Flagstaff, Arizona                     |                                   |
|                                        | VMS just keeps going and going and|
| acm@nauvax                   BitNet    | going.  Nothing outlasts VAX/VMS. |
| [e-mail]       Internet  |                                   |
| 602.523.9422.us.west         Noise net |                                   |
+----------------------------------------+-----------------------------------+


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