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From: khb@chiba.Eng.Sun.COM (Keith Bierman - SPD Advanced Languages)
Newsgroups: comp.lang.fortran
Subject: Re: Help! How to read SUN keyboard chars in SUN FORTRAN?
Message-ID: <KHB.90Aug1204402@chiba.Eng.Sun.COM>
Date: 2 Aug 90 03:44:02 GMT
References: <2587.26b69a29@csc.anu.oz>
Sender: news@sun.Eng.Sun.COM
Organization: Sun MegaSystems
Lines: 74
In-reply-to: kjm100@csc.anu.oz's message of 1 Aug 90 09:00:24 GMT


In article <2587.26b69a29@csc.anu.oz> kjm100@csc.anu.oz writes:

   I would be very grateful if anyone could tell me how to read keyboard 
   characters --- one at a time without echoing those characters to the 
   terminal --- within a SUN FORTRAN program.  One would think that using 
   the integer function GETC would do the trick but no ...

It isn't hard, but perhaps we do need another example or two ;> (note
that the f77v1.3 docset is already about 2x the size of previous editions...)

First a f77 driver:

      program bork
c
c     Example of how a program like login works:
c
      integer getc_noecho
      character*1 char/" "/

      write(6,'("enter password ",$)') 
      call flush(6)                     ! make sure we see the prompt
      istat=getc_noecho(char)
      do while (istat .gt. 0)
         write(6,*) "char = ",char
         istat=getc_noecho(char)
      end do
      print*," look ma, no hands "
      end

This will print out "enter password " and wait for input. We'll read
the buffer one byte at a time until an end of file (^D) is input. We
will be tacky and print out each character, one to a line, to prove
the characters are, indeed being read.


Here is the C code for getc_noecho

/* emulate getc, but don't echo */

#include <termios.h>

getc_noecho_(buf)
char buf[];

{

	struct termios old, new;

	int rv;       /* return value */

	int size;     /* this is quite tacky; one might prefer a buffer */
	int fd;       /* at a time ... or to use any file .... */
	size=1; fd=0; /* then size, fd would be arguments      */

	if (ioctl(fd, TCGETS, &old) == -1) return -1;
	new = old;
	new.c_lflag &= ~ECHO;                          /* ioctl is the magickey */
	if (ioctl(fd, TCSETS, &new) == -1) return -1;
	rv = read (fd, buf, size);
	if (ioctl(fd, TCSETS, &old) == -1) return -1;
	return rv;
}

More elegant (or more suited to your application) implementations are
left as an exercise to the reader.



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Keith H. Bierman    kbierman@Eng.Sun.COM | khb@chiba.Eng.Sun.COM
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