Re: wait does not perform as expected

[Daniel Gaudry <gaudry.dg@gmail.com>]

On Thursday, February 23, 2023 at 7:29:36 PM UTC+1, Niklas Holsti wrote:
> On 2023-02-23 20:14, Dmitry A. Kazakov wrote: 
> > On 2023-02-23 18:35, Niklas Holsti wrote: 
> >> On 2023-02-23 16:26, AdaMagica wrote: 
> >>> Niklas Holsti schrieb am Mittwoch, 22. Februar 2023 um 18:36:06 UTC+1: 
> >>>> On my system, Get_Immediate does /not/ use the inputs collected (but 
> >>>> not 
> >>>> "consumed") by Look_Ahead, but instead checks if there are _new_ input 
> >>>> keystrokes. If there are none, Get_Immediate returns "not Available" 
> >>>> (Hit is False) and so the loop continues. 
> >>> 
> >>> Are you sure? 
> >> 
> >> That is what I observe. 
> > 
> > The implementation of Look_Ahead calls getc followed by ungetc. Thus it 
> > blocks until an input if there is no buffered. And not just input, but 
> > for a line or file end.
> That seems in order. 
> 
> However, the crux of the question is in Get_Immediate. Do you know how 
> that is implemented on various systems? It has to disable line buffering 
> and line editing on the input stream. One question is whether and how 
> such "tty" configuration changes affect whatever buffers getc/ungetc use. 
> 
> On my system, if Look_Ahead uses getc and ungetc, it seems Get_Immediate 
> does not use the same buffers, and has no effect on those buffers. That 
> could be desirable behaviour in some cases, undesirable in others. 
> 
> On AdaMagica's system, it seems that Get_Immediate uses the same buffers 
> as Look_Ahead (getc/ungetc).


Hi,
On my ubuntu system the 
ada.text_io.GET_IMMEDIATE(ITEM => CHAR, AVAILABLE => HIT);
just pause the program regardless of any key being hit.
I just cannot use a wait  (several shorts one in a row) interrupted by a key hit.
Any possibility you may know of ??
My Best Regards