non-blocking input

[cottrell at nbs-vms.ARPA]

/*
> I am working an a very simple game using graphics text with a
> GiGi terminal.  I am having a big problem with the input.  When
> I get to a read, or any input statment, in C, everything stops
> and waits for the input.
> 
> I want to be able to have the program check for keyboard input, and 
> if it is there to act upon it, otherwise to continue processing.
> Is there an easy way to do this in C.  I am doing this on a VAX
> runnung 4.2 if that makes a difference.  
> 
> I have played around with the low leval input described in a V7
> manual, but couldn't get any where.  My next thought is to fork
> off a process for the background and one for the user's charactor
> and then use a semaphore to allow access to the graphics cursor.
> Is this nessassary, and if it is, any hints on what to watch out
> for?
> 
> Thanks to all.
> 
> scott hossler
> rochester!ritcv!sah9577

Try `select', or `open' with O_NDELAY. Both are described in sexion 2.

	jim
*/