Traditionally, the proper solution to avoid deep copies is to wrap a std::shared_ptr<std::string> instead of a std::string directly.
If your strings are short of course, it may well be faster to leave it as is. std::shared_ptr is not lightweight and may use atomic instructions, the bandwidth for which in a system is always limited. Niall On 23 Dec 2012 at 16:16, simon zhang wrote: > ..so,It seems I can only convert std::string and make a deep copy.I can > only avoid it as much as possible.Thank you. > > > 2012/12/22 Jim Bosch <tallji...@gmail.com> > > > On 12/21/2012 03:52 AM, simon zhang wrote: > > > >> How to converter std::string* in boost.python?I have to handle some data > >> of c++ in python.The data may be big.So I return a pointer to python. > >> But there are some errors. > >> > >> > > If the data is big, and you really want to avoid a deep copy, the only way > > to use it is if you manually allocate the memory as a Python str object > > using the Python C API or return it as something else (like a NumPy array > > or buffer object, or a custom Boost.Python-wrapped class) that can hold > > C++-allocated memory. A Python str object always owns its own memory, and > > so does std::string, so you can't convert from one to the other without a > > deep copy. > > > > Jim > > > > ______________________________**_________________ > > Cplusplus-sig mailing list > > Cplusplus-sig@python.org > > http://mail.python.org/**mailman/listinfo/cplusplus-sig<http://mail.python.org/mailman/listinfo/cplusplus-sig> > > > -- Any opinions or advice expressed here do NOT reflect those of my employer Research In Motion Inc. Work Portfolio: http://careers.stackoverflow.com/nialldouglas/
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