[C++-sig] Re: Python string -> const char * + size_t

[Eric Hopper]

Dave Abrahams wrote:
> Eric Hopper wrote:
>> The hash function is only going to read it and munge it a bit, so as
>> long as the data remains around for the duration of the call, it's
>> not a problem.
>>
>> I want to somehow pass a Python string to an interface something like:
>>
>> class Something {
>>  public:
>>    void hash_data(const char *data, size_t datalen);
>> };
>>
>> What is the easiest and cleanest way to make this happen using
>> boost::python?
> 
> Well, if you need the length it's a little harder.  Make a thin
> wrapper function that accepts a boost::python::str object x, then use
> 
>         x.ptr()
> 
> to get the PyObject* and use the Python/C API to get the pointer and
> length.

That worked like a charm.  I thought that might be the answer, but I was
a bit worried that ::boost::python::str made a copy.  I'm glad to learn
that it doesn't.  :-)

Thanks,
-- 
"It does me no injury for my neighbor to say there are twenty gods or no God.
It neither picks my pocket nor breaks my leg."  --- Thomas Jefferson
"Go to Heaven for the climate, Hell for the company."  -- Mark Twain
-- Eric Hopper (hopper at omnifarious.org  http://www.omnifarious.org/~hopper) --
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