beginner needs help with design/planning report-functionality in C++ Application

I'm somehow stuck with implementing a reporting functionailty in my Log-Parser Application.

This is what I did so far:

I'm writing an Application that reads Logfiles and searches the strings for multiple regular Expressions that can be defined in a user-configuration file. For every so called "StringPipe"-defintion that is parsed from the configuration the Main-Process spawns a worker thread that will search for a single regex. The more definitons the user creates, the more worker threads are spawned. The Main Function reads a bunch of Logstrings and then sends the workers to process the strings and so on.

Now I want every single worker thread that is spawned to report information about the number of matches it has found, how long it took, what it did with those strings and so on. These Information are used to export as csv, write to DB and so on.

Now I'm stuck at the point where I created a Class "Report". This Class provides member functions that are called by the worker threads to make the Report-Class gather the Infos needed for generating the report.

For that my workers (which are boost::threads / functors) have to create a Report-Object which they can call those reporting functions for.

The problem is in my Design, because when a worker-thread finishes his job, it is destroyed and for the next bunch of strings that needs to be processed a new instance of this worker functor is spawned and so it needs to create a new Report Object.

This is a problem from my understanding, because I need some kind of container where every worker can store it's reported infos into and finally a global report that contains such infos as how long the whole processing has taken, which worker was slowest and so on.

I just need to collect all these infos together, but how can I do this? Everytime a worker stops, reports, and then starts again, it will destroy the Report-Object and it's members, so all the infos from previous work is go开发者_StackOverflow社区ne.

How can I solve this problem or how is such a thing handled in general?

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First, I would not spawn a new thread do the RE searching and such. Rather, you almost certainly want a pool of threads to handle the jobs as they arise.

As far as retrieving and processing the results go, it sounds like what you want are Futures. The basic idea is that you create an object to hold the result of the computation, and a Future to keep track of when the computation is complete. You can either wait for the results to be complete, or register a call-back to be called when a future is complete.

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Instead of having the worker thread create the report object, why don't you have the main thread create the empty report and pass a pointer to the worker thread when created. Then the worker thread can report back when it has completed the report, then the main thread can add the data from that report to some main report.

So, the worker thread will never have ownership of the actual report, it fill just populate its data fields and report back to the main thread.