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Obtaining user input within a DCL procedure?

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The Question is:

 
Hello,
 
I previously wrote about how while using curses in a C program I couldn't
get getch() and getc() to get keyboard characters.  It has turned out to be
a probelm at the command line.
 
I invoked the exe file from within a DCL .com file.
When I executed the commands manually getch and getc could read from the
keyboard.
 
x.com contains:
 
$x:=$home:[myhome]x.exe
$x data_in_parameter
 
Executing the .com file, @x, caused x.exe to
execute but couldn't read from the keyboard.
 
Please let me know if you can help.
 
THX,
mitch
 

The Answer is :

  While executing a command procedure, SYS$INPUT ("standard input") points
  to the command procedure itself, with the next line starting with "$"
  being seen as EOF (see the $DECK command to change the EOF marker).
 
  If you wish to read input from the terminal, from a program run within
  a procedure, you must redirect standard input. Use the command:
 
  	$ DEFINE/USER SYS$INPUT SYS$COMMAND
 
  SYS$COMMAND is the terminal keyboard, so be redefining the logical name
  SYS$INPUT to SYS$COMMAND, input will be read from the terminal. The
  /USER makes this a user mode logical name definition. As such, it will
  automatically be deassigned at the next image exit. So, the sequence:
 
	$ DEFINE/USER SYS$INPUT SYS$COMMAND
	$ RUN PROGRAMA
	$ RUN PROGRAMB
	some input for PROGRAMB
	another line of input for PROGRAMB
	$ RUN PROGRAMC
	$ EXIT
 
  Input for PROGRAMA will be read from the terminal keyboard, while input
  for PROGRAMB will be read from the procedure itself. Since there are no
  lines after "$ RUN PROGRAMC" which don't start with "$", any attempt to
  read from standard input will result in an immediate EOF.
 
  Also note that you can replace your commands:
 
	$x:=$home:[myhome]x
	$x data_in_parameter
 
  with:
 
	$ MCR home:[myhome]x data_in_parameter
 
  Or, using DCL$PATH once (say in your login procedure) to include the
  directory home:[myhome]. For example:
 
	$ DEFINE DCL$PATH home:[myhome]
 
  From there on:
 
	$ x data_in_parameter
 
  and, any other programs or procedures in home:[myhome] can be executed
  by typing just its name (makes all those Unix and DOS folk feel at home).

  

     

     
answer written or last revised on ( 29-NOV-1998 )
     
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