Re: [Boost-users] [thread] Is Boost suitable for this application?

Subject: Re: [Boost-users] [thread] Is Boost suitable for this application?
From: Francisco Javier Porras Gálvez (francisco.porras.78_at_[hidden])
Date: 2010-06-06 22:02:55

----- Original Message ----- 
From: "Jerry" <jerry.jeremiah_at_[hidden]>
To: <boost-users_at_[hidden]>
Sent: Monday, June 07, 2010 2:22 AM
Subject: Re: [Boost-users] [thread] Is Boost suitable for this application?

> Francisco Javier Porras Gálvez <francisco.porras.78 <at> hotmail.com> 
> writes:
>
>>
>>
>> Hi, all.
>>
>> I don't know anything about Boost, neither OpenMP,
>> pthread nor Windows API thread library. So, before begin learning one of
>> these, I'd like to explain to you how I want my application to work.
>>
>> It deals with running two parallel loops, one in LabView, and the other 
>> in
>> C++. It doesn't matter if you don't know anything about LabView, this
>> explanation is easy enough to understand. Attached you can see a picture
>> which shows the desired execution behaviour. I want to know whether my
>> application would be possible to achieve using Boost, or using another
>> API. In another general C++ forum, I was suggested to use Boost.
>>
>> First, the execution begins in LabView. Here, I call a dll function 
>> written
>> in C++. This is the "initialization" function. Its aim is to create 
>> another
>> thread that will execute the main loop in C++. Then, this 
>> "initialization"
>> function ends, because it has to return the control execution to LabView,
>> but the new thread which has just been created must continue executing in
>> its own loop.
>>
>> Now we have two loops in parallel: LabView and C++. In LabView's loop, we
>> call periodically another dll function that has to send and retrieve data
>> from the independent thread in C++. This function, like the other, has to
>> end executing to pass control to LabView again, after it has done its
>> purpose.
>>
>> This will be the behaviour until we call from LabView another dll 
>> function
>> to stop the independent thread (not shown in the picture). After this, 
>> the
>> LabView program ends.
>>
>> Is it possible to use Boost for this? If so, could
>> you post a brief example about how you'd make it?
>>
>> Thanks in advance,Francisco
>
> I did something almost exactly like this about 10 years ago with LabView 
> 7.  I
> made a DLL that created a thread that started a socket listner so that 
> other
> computers could connect to the embedded Labview to get control data.
>
> Now, Labview allows you to create sockets, but the protocol library for 
> the
> socket data was already in C++ and I tried to create the socket in Labview 
> and
> pass it into the DLL but I had quite a bit of trouble.  It didn't work
> correctly in Labview 7.  I raised a ticket with NI and they basically 
> couldn't
> help me because none of their help desk knew anything about making your 
> own
> DLL.  Hopefully the support is better now.
>
> So anyway, I created a DLL that started a thread and created a socket
> listner.  Then periodically I would call another function in the DLL to
> deposit control data that the socket listener could send to requestors.  I 
> had
> it start a separate thread because I was using a blocking socket listener.
>
> It all works fine.  And from Labview's point of view it doesn't matter 
> what
> library you use to create the socket because all that is hidden in the 
> DLL.  I
> used Visual Studio's C runtime beginthread function and that worked 
> because
> the embedded Labview system was running on Windows, but of course it isn't
> portable (neither is pthread or Windows API threads).  Boost Threads is
> portable and would work fine.
>
> Do you know what OS your Labview app will be running on?
>
> Jerry
>
>
>
>
>
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Hi, Jerry.

Thanks for your support!

I hadn't any idea about what a socket was, but after "googling" a little and 
read about in NI pages, I have it clearer now.

LabView uses a tool called DataSocket to share data between different 
applications or/and the internet. Moreover, I "discovered" that LabView 
includes a set of C++ libraries in what is called "Measurement Studio". One 
of this libraries implements also "DataSocket", and in NI forums they state 
is possible to share data between two applications in C++ and LabView using 
this DataSocket tool.

So, I think this is the right direction. Your clue was really useful.

Thanks,
Francisco