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In C++, during a class constructor, I started a new thread with this pointer as a parameter which will be used in the thread extensively (say, calling member functions). Is that a bad thing to do? Why and what are the consequences?
My thread start process is at the end of the constructor.
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Some people feel you should not use the this pointer in a constructor because the object is not fully formed yet. However you can use this in the constructor (in the { body } and even in the initialization list) if you are careful.
ap is a pointer variable, so declaring it or assigning to it does not call any constructor.
The code in the constructor is really just to perform additional initialization once the object is constructed. So it is perfectly valid to use a "this" pointer in a class' constructor and assume that it points to a completely constructed object.
The consequence is that the thread can start and code will start executing a not yet fully initialized object. Which is bad enough in itself.
If you are considering that 'well, it will be the last sentence in the constructor, it will be just about as constructed as it gets...' think again: you might derive from that class, and the derived object will not be constructed.
The compiler may want to play with your code around and decide that it will reorder instructions and it might actually pass the this pointer before executing any other part of the code... multithreading is tricky
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