# Ruby thread is buggy while using serialport **URL:** \ **Category:** Ruby\ **Created:** [August 7, 2009, 2:57pm UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372 "2009-08-07T14:57:22Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![ashikalim](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@ashikalim](https://www.ruby-forum.com/u/ashikalim)\ **Post date:** [August 7, 2009, 2:57pm UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372/1 "2009-08-07T14:57:22Z")
Hi all , I am using following gems . ``` gem1.8 list ``` \*\*\* LOCAL GEMS \*\*\* actionmailer (2.3.2) actionpack (2.3.2) activesupport (2.3.2) ruby-ole (1.2.8.2) ruby-serialport (0.7.0) spreadsheet (0.6.3.1) xml-simple (1.0.12) ``` I am using modem . By using the serialport I am accessing the modem ``` port . while using the .sysread or read get blocked although I set .read\_timeout = -1 But in fork it is working properly . log is ,irb(main):001:0\> require ‘rubygems’ =\> true irb(main):002:0\> require ‘serialport’ =\> true irb(main):003:0\> sp = SerialPort.new( “/dev/ttyPS1” , 115200 ) =\> #SerialPort:0xb796b074 irb(main):004:0\> sp.read\_timout NoMethodError: undefined method `read_timout' for # from (irb):4 irb(main):005:0> sp.read_timeout => 0 irb(main):006:0> sp.read_timeout = -1 => -1 irb(main):007:0> sp.sysread 45 EOFError: end of file reached from (irb):7:in`sysread’ from (irb):7 irb(main):008:0\> sp.sysread 45 EOFError: end of file reached from (irb):8:in `sysread' from (irb):8 irb(main):009:0> sp.sysread 45 EOFError: end of file reached from (irb):9:in`sysread’ from (irb):9 irb(main):010:0\> sp.sysread 45 EOFError: end of file reached from (irb):10:in `sysread' from (irb):10 irb(main):011:0> sp.sysread 45 EOFError: end of file reached from (irb):11:in`sysread’ from (irb):11 irb(main):012:0\> fork { irb(main):013:1\* sp.sysread 45 irb(main):014:1\> } (irb):13:in `sysread': end of file reached (EOFError) from (irb):13:in`irb\_binding’ from (irb):12:in `fork' from (irb):12:in`irb\_binding’ from /usr/lib/ruby/1.8/irb/workspace.rb:52:in `irb\_binding’ from /usr/lib/ruby/1.8/irb/workspace.rb:52 =\> 9425 irb(main):015:0\> Thread.new(sp){ |sp| irb(main):016:1\* sp.sysread 43 irb(main):017:1\> } =\> #\ irb(main):018:0\> Thread.new(sp){ |sp| irb(main):019:1\* p “before” irb(main):020:1\> sp.sysread 43 irb(main):021:1\> p “asdf” irb(main):022:1\> } “before”=\> #\ \< blocked\> Can any one help me to resolve this? cheers , ashikali ---
**Author:** ![ashikalim](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@ashikalim](https://www.ruby-forum.com/u/ashikalim)\ **Post date:** [August 8, 2009, 8:14pm UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372/2 "2009-08-08T20:14:38Z")
> “before”=\> #\ > \< blocked\> My guess is that serialport library has no way of knowing if it has any data incoming [it has to poll until data arrives?] If that’s the case, then you might could use fork plus some of the excellent fork libraries available [http://allgems.ruby-forum.com/gems?search=fork](http://allgems.ruby-forum.com/gems?search=fork) or you’d need to “fix” serialport so that it’s 1.9 compatible, and then wrap its read call in an rb\_thread\_blocking\_region, so that it allows other threads to operate. GL. -r ---
**Author:** ![ashikalim](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@ashikalim](https://www.ruby-forum.com/u/ashikalim)\ **Post date:** [August 12, 2009, 6:40am UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372/3 "2009-08-12T06:40:33Z")
Roger P. wrote: > > “before”=\> #\ > > \< blocked\> > > My guess is that serialport library has no way of knowing if it has any > data incoming [it has to poll until data arrives?] > If that’s the case, then you might could use fork plus some of the > excellent fork libraries available > [http://allgems.ruby-forum.com/gems?search=fork](http://allgems.ruby-forum.com/gems?search=fork) or you’d need to “fix” > serialport so that it’s 1.9 compatible, and then wrap its read call in > an rb\_thread\_blocking\_region, so that it allows other threads to > operate. > GL. > -r No I am using frok only . It is working fine no problem . Also while traping simultaneous SIGCLD also it does not working properly . Please fix it and makes rubyserial compactable with thread and Traping signal . cheers, ashik ali ---
**Author:** ![ashikalim](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@ashikalim](https://www.ruby-forum.com/u/ashikalim)\ **Post date:** [August 12, 2009, 11:40am UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372/4 "2009-08-12T11:40:45Z")
On Aug 12, 6:40 am, Ashikali A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > serialport so that it’s 1.9 compatible, and then wrap its read call in > > an rb\_thread\_blocking\_region, so that it allows other threads to > > operate. > > GL. > > -r > > No I am using frok only . It is working fine no problem . > > Also while traping simultaneous SIGCLD also it does not working properly You are passing in the same object to different threads. So the threads call methods on the same object. Try creating a SerialPort.new inside the thread. With fork, you generate a seperate ruby process with seperate objects. ---
**Author:** ![ashikalim](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@ashikalim](https://www.ruby-forum.com/u/ashikalim)\ **Post date:** [August 12, 2009, 2:47pm UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372/5 "2009-08-12T14:47:30Z")
> I have to inform you another problem . Al though I am using Thread for > one serial > port let us say /dev/ttyPS0 . > > It is blocking another serial devive /dev/ttyPS2 . I could not > understand why thread is blocking another serial device too while using > serialport library . Are they both being read from within the same process, in different threads? -r ---
**Author:** ![ashikalim](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@ashikalim](https://www.ruby-forum.com/u/ashikalim)\ **Post date:** [August 12, 2009, 3:00pm UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372/6 "2009-08-12T15:00:37Z")
Roger P. wrote: > > I have to inform you another problem . Al though I am using Thread for > > one serial > > port let us say /dev/ttyPS0 . > > > > It is blocking another serial devive /dev/ttyPS2 . I could not > > understand why thread is blocking another serial device too while using > > serialport library . > > Are they both being read from within the same process, in different > threads? > -r yes , of course . Please have look on attached modemThread.rb file . ---
**Author:** ![ashikalim](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@ashikalim](https://www.ruby-forum.com/u/ashikalim)\ **Post date:** [August 12, 2009, 2:28pm UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372/7 "2009-08-12T14:28:58Z")
removed\_email\_address@domain.invalid wrote: > On Aug 12, 6:40�am, Ashikali A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > > serialport so that it’s 1.9 compatible, and then wrap its read call in > > > an rb\_thread\_blocking\_region, so that it allows other threads to > > > operate. > > > GL. > > > -r > > > > No I am using frok only . It is working fine no problem . > > > > Also while traping simultaneous SIGCLD also it does not working properly > > You are passing in the same object to different threads. So the > threads call methods on the same object. > > Try creating a SerialPort.new inside the thread. > > With fork, you generate a seperate ruby process with seperate objects. I have to inform you another problem . Al though I am using Thread for one serial port let us say /dev/ttyPS0 . It is blocking another serial devive /dev/ttyPS2 . I could not understand why thread is blocking another serial device too while using serialport library . Please go through the attached source code . For your reference . ---
**Author:** ![ashikalim](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/9dc877/32.png) [@ashikalim](https://www.ruby-forum.com/u/ashikalim)\ **Post date:** [August 12, 2009, 3:04pm UTC](https://www.ruby-forum.com/t/ruby-thread-is-buggy-while-using-serialport/173372/8 "2009-08-12T15:04:42Z")
Ashikali A. wrote: > Roger P. wrote: > > > > I have to inform you another problem . Al though I am using Thread for > > > one serial > > > port let us say /dev/ttyPS0 . > > > > > > It is blocking another serial devive /dev/ttyPS2 . I could not > > > understand why thread is blocking another serial device too while using > > > serialport library . > > > > Are they both being read from within the same process, in different > > threads? > > -r > > yes , of course . > > Please have look on attached modemThread.rb file . One port is in same process another one in therad . please go through the attached modemThread.rb in previous .