# getch - get a character from file fd.
# NOTE - RDOS/AOS differences below
include ratdef
   integer function getch (c, fd)
   integer c, fd
   include channel
   
   if (0 <= fd & fd <= MAXCHNL & channel(fd) ^= ERR) {
      if (md(fd) ^= READ) {
	 md(fd) = READ; ic(fd) = 1; nc(fd) = 0
	 }
      repeat {
	 if (nc(fd) < ic(fd)) {			 # fill the buffer.
	    nc(fd) = 0
	    call rdlin (fd, linebuf(1,fd), nc(fd), ier)
	    call chkio (fd, ier)
	    ic(fd) = 1
	    }
	 if (nc(fd) < ic(fd)) c = EOF		 # we must have hit eof!
	 else {
	    c = byte(linebuf(1,fd), ic(fd)) & 177k
	    ic(fd) = ic(fd) + 1
#  comment out next two lines if AOS, keep if RDOS
#	    if (c == NEWLINE) c = NULL		# change NEWLINE to NULL
#	    else if (c == CR) c = NEWLINE	# change CR to NEWLINE
	    }
	 }
      until (c == EOF | c ^= NULL)		 # get rid of null's
      }
   else c = EOF
   
   return (c)
   end