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This queue is for tickets about the Device-SerialPort CPAN distribution.

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The Basics
Id: 78431
Status: new
Priority: 0/
Queue: Device-SerialPort

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Owner: Nobody in particular
Requestors: m.ramakers [...] gmail.com
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Bug Information
Severity: Normal
Broken in: 1.04
Fixed in: (no value)



Subject: status() unnecessarily disabled on NetBSD host
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ENVIRONMENT: tested on NetBSD 6.0BETA2 / i386 and Device::SerialPort 1.04. I did not test on Linux, although I think behaviour would be ok (see 'ANALYSIS': ioctl 'TIOCINQ' is present in bits/ioctls.h on Linux systems, afaik). DESCRIPTION: 'Device::SerialPort::status()' is inconveniently disabled as per 'can_status()', making it necessary to use 'Device::SerialPort::ioctl( "TIOCOUTQ", \$num_byte )' to read the number of bytes pending write in the output-buffer. If not necessary, it would IMHO be better to do this without explicit ioctls. TO REPRODUCE: 1 #!/usr/pkg/bin/perl 2 3 use strict; 4 use warnings; 5 use Device::SerialPort; 6 7 my $port = Device::SerialPort->new( "/dev/ttyU0" ) or die; 8 $port->can_status() or die; # on NetBSD, execution fails here (alternatively, list known ioctls using a oneliner - see 'SUGGESTED FIX'.) ANALYSIS: Implementation of 'status()' (SerialPort.pm): 1870 sub status { 1871 my $self = shift; 1872 return if (@_); 1873 return unless ($self->can_status); (i.e. precondition for this function to work is 'can_status()' returning true) Implementation of 'can_status()' (SerialPort.pm): 702 sub can_status { 703 return 1 if (defined($bits->{'portable_TIOCINQ'}) && 704 defined($bits->{'TIOCOUTQ'})); 705 return 0; 706 #return 0 unless ($incount && $outcount); 707 #return 1; 708 } On NetBSD, 'TIOCOUTQ' is found at compile-time (namely, in /usr/include/sys/ttycom.h). A pseudo-flag 'portable_TIOCINQ' is used instead of 'TIOCINQ' (SerialPort.pm): 91 # Set alternate bit names 92 $bits->{'portable_TIOCINQ'} = $bits->{'TIOCINQ'} || $bits->{'FIONREAD'}; This is fine, since TIOCINQ and FIONREAD are the same, from what I understood. On NetBSD, TIOCINQ is not found at compile-time, but FIONREAD is (namely, in /usr/include/sys/filio.h). The '$bits' hash is constructed in the build-process (SerialPort.xs): 99 #ifdef TIOCINQ 100 ADD_TO_HASH(TIOCINQ) 101 #endif 102 #ifdef TIOCOUTQ 103 ADD_TO_HASH(TIOCOUTQ) 104 #endif However, a similar clause for 'FIONREAD' is not present - it seems the fallback to 'FIONREAD' as substitute to 'TIOCINQ' was not completely implemented. SUGGESTED FIX: add a clause for 'FIONREAD' to SerialPort.xs: #ifndef FIONREAD ADD_TO_HASH(FIONREAD) #endif To verify effect of fix without actually opening a port: $ perl -MDevice::SerialPort -MData::Dumper -e 'print Data::Dumper::Dumper Device::SerialPort::Bits::get_hash()' | grep FIONREAD ...returns nothing before, and returns 1 entry after the fix. I also verified the functionality of 'status()' after the fix w.r.t. bytes in output-buffer, which worked fine. WORKAROUND: to get number of bytes in output-buffer, use 'Device::SerialPort::ioctl()' as alternative, as stated in the manual: my $mstat = " "; $my_serial_port->ioctl( 'TIOCOUTQ', \$mstat ) or die; my $count = unpack( 'L', $mstat ); print "there are $count bytes pending write\n";
From: m.ramakers [...] gmail.com
also reported as NetBSD issue 'pkg/46713'


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