Re: [Boost-users] Thread within thread

From: Ben Hutchings (ben.hutchings_at_[hidden])
Date: 2004-12-13 14:52:44

Leon Mergen wrote:
> Hello everyone,
> 
> I'm currently attempting to create a thread within a thread, and for
> some reason, the constructor seems to block and things just don't work
> very well.
> 
> Consider a class ``BackupHandler'' and a class ``BackupHandlerThread''
> - the thread is created for once in the 50ms polling to an output file
> which  might be used by other processes. Now, in BackupHandler, I do this:
> 
> ---
> boost::thread thread ( BackupHandlerThread (this->backupFile, this->data) );
> ---
> 
> Which, as far as I am aware of, should first create a
> BackupHandlerThread object, and then "launch" the thread with this
> object. Now, since I print out some debug info, it seems like it
> reaches the BackupHandlerThread constructor once, and the destructor
> twice.
<snip>

This calls the constructor you expected once, and then the copy 
constructor as well.  If you don't want the BackupHandlerThread to be 
copied, I think you need to construct it other than as a temporary and 
pass a reference wrapper (boost::ref<BackupHandlerThread>) to the thread 
constructor.

Ben.