[Info-vax] DCL "READ/TIME_OUT=n" from terminal; timer resets if message written to screen

[Scott Snadow]

On Saturday, May 22, 2021 at 2:13:33 AM UTC-5, Volker Halle wrote:

> this is expected and documented behaviour. It has nothing to do with DCL. 
> 
> https://vmssoftware.com/docs/VSI_IO_REF.pdf 
> 
> Table 5.6. Read QIO Function Modifiers for the Terminal Driver 
> 
> IO$M_TIMED ... 
> If a read operation is interrupted by either a broadcast write or a synchronous write request, the timer operation is restarted. 

Look at that.  It *IS* documented!  Thanks Volker for pointing me to that.  It also makes sense that it's buried inside of the terminal driver and not in DCL, since I couldn't imagine that DCL would actually be coded to be aware of incoming writes to the terminal from other processes.

VSI, if you're reading this, a documentation enhancement request: Please mention this in the DCL Manual and also in "HELP READ /TIME_OUT" since a casual DCL programmer probably wouldn't be perusing the I/O User's Reference Manual very often!

Scott