non-blocking reading

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hello

I have this piece of code to read from a serial port

sysread(COM,$buf,1);
unpack("C*",$buf);
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but it seems to never time out if there is nothing to read. Is there a non-blocking system equivalent (that's to say, not using the SerialPort module) to the above code - one where I can control the timeout value?

Comment on non-blocking reading Download Code

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Re: non-blocking reading
by grep (Monsignor) on Feb 06, 2002 at 05:57 UTC

Fcntl

F_SETFL  Set  the descriptor's flags to the value specified by arg.  
                Only O_APPEND, O_NONBLOCK and O_ASYNC
                may be set; the other flags are unaffected.
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FAQ - How do I open a file without blocking?
non-blocking accept

On asking for help
How to ReadTheFineManual

know thy FAQ - search is your friend

grep

grep> chown linux:users /world

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[d/l]

Use select function or adjust flag bits of mode parameter to sysopen - Re: non-blocking reading
by metadoktor (Hermit) on Feb 06, 2002 at 05:48 UTC

select

UPDATE: I found this node which explains what the mode should be for the sysopen.

metadoktor

"The doktor is in."

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