It is important that resources are reclaimed when exceptions are thrown. Throwing an exception may result in cleanup code being bypassed. As a result, it is the responsibility of the exception handler to properly cleanupclean up. This may be problematic if the exception is to be caught in a different function or module. Instead, it is preferable if resources are reclaimed automatically when objects go out of scope.
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In this code, the exception handler recovers the resources accociated associated with the object pointed to by pst.
It might be better to replace the pointer pst with an auto_ptr which that automatically cleans up itself.
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