Hey Dave,

Thanks for the info.  Looking at the code, I see that ExternalUnixOSProcess
is returned from "OSProcess command:...".  It has some nice methods for
checking if the command finished ok.

I added some code to the method that calls irsend to check if the command
is finished and if it was successful, looping on a small delay.  If after
awhile it has not finished successfully I try again for a few times and
then give up.  Since I'm sure the irsend command is fine, the errors should
just be transient of the odd timing nature and retrying should work.

Lou

>There are a couple of ways that a unix program can provide error output.
>The exit status is a simple way to communicate either success, or one of
>possibly several not so successful outcomes. This is useful for programs
>that are used in shell scripts for example. The other way is for the
>program to write error messages to its stderr output stream. This is
>common for programs for which which a user is expected to read the error
>messages.
>
>I don't see anything in the man page for irsend that explains the exit
>status values, so it's a good bet that 0 means goodness and anything
>else means not so good. That might not be enough information to change
>the channel on your TV, but as you say I'd go ahead and try that first
>and see if it is good enough.
>
>If you need to read the error output from the stdout stream (i.e. the
>error messages that would normally go to the console when you run
>the irsend program), you can do this by loading the CommandShell
>package from SqueakMap, then do something like this:
>
>irsend := ProxyPipeline command: 'irsend foo bar baz'.
>
>irsend last processProxy ==> an ExternalUnixOSProcess with pid 4157 on /usr/bin/irsend (complete, normal termination with status 1)
>
>irsend errorUpToEnd ==> 'irsend: could not connect to socket
>irsend: No such file or directory
>'
>
>But I think this is more complexity than you really need for this, so
>definitely you should first try just checking for exit status 0 and see
>if that does what you need.
>
>Dave
>
>
>On Thu, Feb 07, 2013 at 11:37:17AM -0500, Louis LaBrunda wrote:
>> Hi Dave,
>> 
>> Last night I left the RasPi running my Squeak code to change the channels.
>> Most worked just fine.  One of the calls to "OSProcess command:..." says it
>> had a "... normal termination with status 1".  It didn't change the
>> channel.  I will look through the code for what this and other status codes
>> mean but can you tell me or point me to some docs.
>> 
>> I would like to test for errors and retry.  For now I think I will just
>> test for non zero.
>> 
>> Lou
>> 
>> On Tue, 5 Feb 2013 17:22:50 -0500, "David T. Lewis" <lewis at mail.msen.com>
>> wrote:
>> 
>> >On Tue, Feb 05, 2013 at 03:55:14PM -0500, Louis LaBrunda wrote:
>> >> 
>> >> >On Mon, Feb 04, 2013 at 02:07:12PM -0500, Louis LaBrunda wrote:
>> >> >> Hi Guys,
>> >> >> 
>> >> >> I would like to call irsend (a program that is part of lirc package) from
>> >> >> Squeak on the Raspberry Pi.  Can anyone please post some sample code.
>> >> >> 
>> >> >
>> >> >I'm not familiar with it myself, but if irsend is just a simple command line
>> >> >program then I should think that you could call it easily using OSProcess.
>> >> >
>> >> 
>> >> Thanks for the reply.  OSProcess sounds like it is what I need but I can't
>> >> find any install instructions, probably because I don't know much about
>> >> Squeak and Linux and I'm not sure where to look.
>> >> 
>> >
>> >Open a SqueakMap Package Loader:
>> >
>> >  world -> open... -> SqueakMap Catalog
>> >
>> >In the SqueakMap Package Loader, select package OSProcess. Expand that
>> >category and you will find entries for version 4.4.11 and for "head".
>> >Either one is fine, but I usually recommend just using the latest version,
>> >so select "head" and install it.
>> >
>> >Assuming that you want to run irsend with some command line parameters,
>> >try inspecting the following expression (but use some command parameters
>> >that actually do something):
>> >
>> >  OSProcess command: 'irsend foo bar baz'
>> >
>> >The result will be an instance of ExternalUnixOSProcess that is a proxy
>> >for the actual irsend program that you just executed. You can send it
>> >#succeeded to see if the command was evaluated without error.
>> >
>> >I think this is sufficient for what you are trying to do, but you can also
>> >do fancier things with external programs if you load CommandShell (also
>> >on SqueakMap).
>> >
>> >For additional background see http://wiki.squeak.org/squeak/708 and
>> >http://wiki.squeak.org/squeak/1914.
>> >
>> >Follow up questions welcome :)
>> >
>> >Dave
>> >
>> >
>> -----------------------------------------------------------
>> Louis LaBrunda
>> Keystone Software Corp.
>> SkypeMe callto://PhotonDemon
>> mailto:Lou at Keystone-Software.com http://www.Keystone-Software.com
>> 
>
-----------------------------------------------------------
Louis LaBrunda
Keystone Software Corp.
SkypeMe callto://PhotonDemon
mailto:Lou at Keystone-Software.com http://www.Keystone-Software.com