Understanding Visibility

Understanding Visibility

[tonyg]

I needed to log some stuff from several tasks in one program. So I wrote a little logging package. I used a package containing several text_io.file_types followed by a protected object to make sure the file operations were not interfered with. 
    However when things were passed through to inside the protected object I found that the file was not taking the information being passed to it. Can anyone explain this to me, as I think the file should be visible. 

Re: Understanding Visibility

[Dmitry A. Kazakov]

On Mon, 17 Sep 2012 13:42:27 -0700 (PDT), tonyg wrote:

> I needed to log some stuff from several tasks in one program. So I wrote a
> little logging package. I used a package containing several
> text_io.file_types followed by a protected object to make sure the file
> operations were not interfered with. 

It is an error to do I/O from a protected action, since I/O is a
potentially blocking operation.

You should either use a task (AKA monitor) or else a protected object
implementing a mutex (using a controlled holder object, of course).

> However when things were passed through to inside the protected object I
> found that the file was not taking the information being passed to it. Can
> anyone explain this to me, as I think the file should be visible.

You should always post a working code illustrating the problem.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: Understanding Visibility

[Thomas Løcke]

On 09/17/2012 10:42 PM, tonyg wrote:
>
> I needed to log some stuff from several tasks in one program. So I wrote a little logging package. I used a package containing several text_io.file_types followed by a protected object to make sure the file operations were not interfered with.
>      However when things were passed through to inside the protected object I found that the file was not taking the information being passed to it. Can anyone explain this to me, as I think the file should be visible.
>


You could take a peek at how they solved the problem in the GNATCOLL
package, specifically the Traces part:

http://docs.adacore.com/gnatcoll-docs/traces.html

It works flawlessly, or rather I've not been able to trash it yet. :D

Another option is Alog from codelabs:  http://www.codelabs.ch/alog/

And a third one is grabbing AWS and look at their AWS.Log package.

Lots of good stuff to learn from.

Personally I use GNATCOLL.Traces for most of my logging needs, as it
can log to syslogd, which I find very handy.

-- 
Thomas L�cke | thomas@12boo.net | http://12boo.net

Re: Understanding Visibility

[tonyg]

On Monday, 17 September 2012 21:42:28 UTC+1, tonyg  wrote:
> I needed to log some stuff from several tasks in one program. So I wrote a little logging package. I used a package containing several text_io.file_types followed by a protected object to make sure the file operations were not interfered with. 
> 
>     However when things were passed through to inside the protected object I found that the file was not taking the information being passed to it. Can anyone explain this to me, as I think the file should be visible.

Thanks Guys, point taken Dmitry, I'll take a look at Traces Thomas.

Re: Understanding Visibility

[tonyg]

On Tuesday, 18 September 2012 07:36:45 UTC+1, Thomas Løcke  wrote:
> On 09/17/2012 10:42 PM, tonyg wrote:
> 
> >
> 
> > I needed to log some stuff from several tasks in one program. So I wrote a little logging package. I used a package containing several text_io.file_types followed by a protected object to make sure the file operations were not interfered with.
> 
> >      However when things were passed through to inside the protected object I found that the file was not taking the information being passed to it. Can anyone explain this to me, as I think the file should be visible.
> 
> >
> 
> 
> 
> 
> 
> You could take a peek at how they solved the problem in the GNATCOLL
> 
> package, specifically the Traces part:
> 
> 
> 
> http://docs.adacore.com/gnatcoll-docs/traces.html
> 
> 
> 
> It works flawlessly, or rather I've not been able to trash it yet. :D
> 
> 
> 
> Another option is Alog from codelabs:  http://www.codelabs.ch/alog/
> 
> 
> 
> And a third one is grabbing AWS and look at their AWS.Log package.
> 
> 
> 
> Lots of good stuff to learn from.
> 
> 
> 
> Personally I use GNATCOLL.Traces for most of my logging needs, as it
> 
> can log to syslogd, which I find very handy.
> 
> 
> 
> -- 
> 
> Thomas Løcke | thomas@12boo.net | http://12boo.net

I noticed that alog has debian wheezy packages supported \o/ so I am taking a good long look at that rather than gnatcoll which needs to be installed from source. Its looking good so far.

Re: Understanding Visibility

[tonyg]

On Tuesday, 18 September 2012 14:47:03 UTC+1, tonyg  wrote:
> On Tuesday, 18 September 2012 07:36:45 UTC+1, Thomas Løcke  wrote:
> 
> > On 09/17/2012 10:42 PM, tonyg wrote:
> 
> > 
> 
> > >
> 
> > 
> 
> > > I needed to log some stuff from several tasks in one program. So I wrote a little logging package. I used a package containing several text_io.file_types followed by a protected object to make sure the file operations were not interfered with.
> 
> > 
> 
> > >      However when things were passed through to inside the protected object I found that the file was not taking the information being passed to it. Can anyone explain this to me, as I think the file should be visible.
> 
> > 
> 
> > >
> 
> > 
> 
> > 
> 
> > 
> 
> > 
> 
> > 
> 
> > You could take a peek at how they solved the problem in the GNATCOLL
> 
> > 
> 
> > package, specifically the Traces part:
> 
> > 
> 
> > 
> 
> > 
> 
> > http://docs.adacore.com/gnatcoll-docs/traces.html
> 
> > 
> 
> > 
> 
> > 
> 
> > It works flawlessly, or rather I've not been able to trash it yet. :D
> 
> > 
> 
> > 
> 
> > 
> 
> > Another option is Alog from codelabs:  http://www.codelabs.ch/alog/
> 
> > 
> 
> > 
> 
> > 
> 
> > And a third one is grabbing AWS and look at their AWS.Log package.
> 
> > 
> 
> > 
> 
> > 
> 
> > Lots of good stuff to learn from.
> 
> > 
> 
> > 
> 
> > 
> 
> > Personally I use GNATCOLL.Traces for most of my logging needs, as it
> 
> > 
> 
> > can log to syslogd, which I find very handy.
> 
> > 
> 
> > 
> 
> > 
> 
> > -- 
> 
> > 
> 
> > Thomas Løcke | thomas@12boo.net | http://12boo.net
> 
> 
> 
> I noticed that alog has debian wheezy packages supported \o/ so I am taking a good long look at that rather than gnatcoll which needs to be installed from source. Its looking good so far.

Did you know that alog can also post to syslog?

Re: Understanding Visibility

[Thomas Løcke]

On 09/18/2012 04:00 PM, tonyg wrote:
>
> Did you know that alog can also post to syslog?
>


Yea, but since I'm using GNATColl rather extensively, I saw no need
to add another dependency to my projects.

-- 
Thomas L�cke | thomas@12boo.net | http://12boo.net

Re: Understanding Visibility

[xavier grave]

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Le 18/09/2012 15:47, tonyg a �crit :
> On Tuesday, 18 September 2012 07:36:45 UTC+1, Thomas L�cke  wrote:
>> On 09/17/2012 10:42 PM, tonyg wrote:
>>
>>>
>>
>>> I needed to log some stuff from several tasks in one program. So I wrote a little logging package. I used a package containing several text_io.file_types followed by a protected object to make sure the file operations were not interfered with.
>>
>>>      However when things were passed through to inside the protected object I found that the file was not taking the information being passed to it. Can anyone explain this to me, as I think the file should be visible.
>>
>>>
>>
>>
>>
>>
>>
>> You could take a peek at how they solved the problem in the GNATCOLL
>>
>> package, specifically the Traces part:
>>
>>
>>
>> http://docs.adacore.com/gnatcoll-docs/traces.html
>>
>>
>>
>> It works flawlessly, or rather I've not been able to trash it yet. :D
>>
>>
>>
>> Another option is Alog from codelabs:  http://www.codelabs.ch/alog/
>>
>>
>>
>> And a third one is grabbing AWS and look at their AWS.Log package.
>>
>>
>>
>> Lots of good stuff to learn from.
>>
>>
>>
>> Personally I use GNATCOLL.Traces for most of my logging needs, as it
>>
>> can log to syslogd, which I find very handy.
>>
>>
>>
>> -- 
>>
>> Thomas L�cke | thomas@12boo.net | http://12boo.net
> 
> I noticed that alog has debian wheezy packages supported \o/ so I am taking a good long look at that rather than gnatcoll which needs to be installed from source. Its looking good so far.

If communication with log4j (or chainsaw) is an option you can have a
look at log4ada, which is also packaged in Debian.

But it can't log to syslog, except if you have time to provide/code an
appender that enable you to do it :)

xavier grave
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Re: netiquette

[Stephen Leake]

tonyg <tonythegair@gmail.com> writes:

> Did you know that alog can also post to syslog?

You really should trim posts; scrolling thru 100 lines of quoted text to
find this is _really_ annoying!

-- 
-- Stephe