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Problem with read data from serial device

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Top Forums Programming Problem with read data from serial device
# 8  
Old 03-06-2010
Quote:
Originally Posted by Corona688

Never call printf from a signal handler. fprintf(stderr, "stuff"); might work since that's unbuffered but even that is not guaranteed. Use write(), along with sprintf if necessary.
For the sake of completeness, it's a bad idea to call fprintf() in a signal handler if the interrupted code also calls fprintf() on the same stream.

Indeed, fprintf() may uses mutex to lock the stream. If it occurs that the signal interrupts fprintf() after it locked the mutex, and fprintf() is called in the signal handler. Well, it's game over: fprintf() shall try to grab again the mutex, and on many implementation this results a deadlock.

Loïc.
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LEARN ABOUT SUSE

rctest

RCTEST(1)																 RCTEST(1)

NAME

       rctest - RFCOMM testing

SYNOPSIS

       rctest <mode> [options] [bdaddr]

DESCRIPTION

       rctest is used to test RFCOMM communications on the BlueZ stack

MODES

       -r     listen and receive

       -w     listen and send

       -d     listen and dump incoming data

       -s     connect and send

       -u     connect and receive

       -n     connect and be silent

       -c     connect, disconnect, connect, ...

       -m     multiple connects

OPTIONS

       -b bytes
	      send/receive bytes bytes

       -i device
	      select the specified device

       -P channel
	      select the specified channel

       -U uuid
	      select the specified uuid

       -L seconds
	      enable SO_LINGER options for seconds

       -W seconds
	      enable deferred setup for seconds

       -B filename
	      use data packets from filename

       -N num send num frames

       -C num send num frames before delay (default: 1)

       -D milliseconds
	      delay milliseconds after sending num frames (default: 0)

       -A     request authentication

       -E     request encryption

       -S     secure connection

       -M     become master

       -T     enable timestamps

AUTHORS

       Written	by  Marcel  Holtmann  <marcel@holtmann.org>  and  Maxim  Krasnyansky  <maxk@qualcomm.com>,  man  page  by  Filippo Giunchedi <fil-
       ippo@debian.org>

BlueZ								    Jul 6 2009								 RCTEST(1)