AW: [En-Nut-Discussion] getch/kbhit

[Harald Kipp]

Hi Oliver,
Hi Brett,
Hi all,

Let me apologize first for taking part here quite rarely.
I'm busy integrating Tyou's ARM7 port into the existing
local stuff here.

On the topic: I assume that it will fail to implement
something general, as devices are very different.
IMHO, kbhit() should check the device type first and
decide what to call.

I doubt, that the current device type classification
(IFTYP_) would be sufficient to solve this.

Another idea is to use dev->dev_size() to return the
number of bytes in the input buffer. The application
or better kbhit() may then call _filelength().
But this is a similar hack as using _read(0) to flush
the input buffer.

I'm undecided. Any other proposals? How did other OSes
handle it? Linux/BSD seem to offer very complicated
mechanisms.

Harald

At 10:18 21.05.2004 +0200, you wrote:
>Hi Brett,
>
>yes, it would run for nut/os 3.4, but it is tied to one specific device, in
>this case an UART. Thus it is not suitable for a "simple" function.
>
>A more general function is not possible, unless we define a 'global' ioctl
>function code (ex: IOCTL_GETSTATUS), which delivers some globaly defined
>status bits.
>After that, it would be possible to write a 'kbhit()' function, that uses
>the stdin file, regardless, which device/file is connected to stdin.
>
>Harald, what do you think?
>
>Cheers,
>Oliver.
>
>
>-----Ursprungliche Nachricht-----
>Von: en-nut-discussion-bounces at egnite.de
>[mailto:en-nut-discussion-bounces at egnite.de]Im Auftrag von Brett Abbott
>Gesendet: Donnerstag, 20. Mai 2004 01:31
>An: en-nut-discussion at egnite.de
>Betreff: [En-Nut-Discussion] getch/kbhit
>
>
>Originally posted May 2003.  Support to test for incoming characters waiting
>is kind of there.  This may help you out
>
>Oliver - Could the test part of this be usefully added to nutos as kbhit? -
>Looks ugly but is pretty straightforward to use.
>
>Regards
>Brett
>
>Hi
>
>The following snippet of code can be used to check for the existance of
>incoming characters without having to actually receive them.  Useful for
>"Press the Return key or wait 10 seconds to reload last known configuration"
>type messages.  Improved versions of version portable code welcomed.
>
>It uses the uart library.  Is there a more generic stream or file function
>call I could use?  I chose this approach rather than write a custom function
>to hopefully support future and past nutos releases.
>
>Hopefully this will save someone some effort.
>
>Cheers
>Brett
>
>// Globals
>FILE *uart;
>u_long UartStatus;
>u_long *UartStatus_ptr;
>
>// Sample Code to check for key press, Assumes uart file already open. Does
>not block if no characters were received.
>
>   // Were any keys pressed?
>   result=UartAvrIOCtl(((NUTFILE *) (_fileno(uart)))->nf_dev, UART_GETSTATUS,
>UartStatus_ptr);
>   if((UartStatus & UART_RXBUFFEREMPTY)==0) // One or more keys were pressed
>        // Now go get it
>        if((rlen = _read(_fileno(uart), rxbuff_ptr, RXBUFF_LEN)) > 0) // Get
>the characters
>           if(strchr(rxbuff_ptr, '\r') || strchr(rxbuff_ptr, '\n'))    // Did
>the user hit <CR> or <LF> ?
>               UserEnterNewConfig();  // Yes? go to Configure mode
>
>
>-----------------------------------------------------------------
>Brett Abbott, Managing Director, Digital Telemetry Limited
>Email: Brett.Abbott at digital-telemetry.com
>PO Box 24 036 Manners Street, Wellington, New Zealand
>Phone +64 (4) 5666-860  Mobile +64 (21) 656-144
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>
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