"Jonathan Graehl" <jonathan@graehl.org> wrote in message news:413535B2.5090105@graehl.org...
Generally: four stars, two thumbs up, and a partridge in a pear tree.
Thanks.
I'm interested in directly using the Windows/POSIX mmap portability wrapper; might we promote it out of the detail namespace? That is, I may want to use mmap to perform some explicit memory swapping/caching.
Yes. I discussed this with Craig Henderson, the original author of Boost.Memmap in the sandbox. Since I ran out of time to document memmap.hpp, I left it as an implementation detail, with the idea that it might be a good candidate for fast track review later. ---- Here's a brief description of the interface of detail::mapped_file and detail::readonly_mapped_file: Both have a std::fstream-like interface, consiting of member functions open()/is_open()/close() and 'opening' constuctors which take the same parameters as open(). A safe-bool conversion and operator! can be used equivalently to is_open() to tell whether the file has been opened and mapped successfully. They also have a std::string-like interface consisting of member functions begin(), end(), data() and size(). (Obviously there is some redundancy here.) detail::mapped_file can be opened in read-only mode; to faciliate this it also has members const_begin(), const_end() and const_data(). There's also a static member alignment() returning the allocation granularity for virtual memory. Both are non-copyable. ----
It looks like I could first create a file of the desired size, then acquire a mapped_file_resource - but then I don't get access to the actual pointer to memory (it's hidden in the private _pimpl). This is fine; what I really want is a portability wrapper for mmap :)
You can get the actual pointer using the functions input_sequence or output_sequence (part of the Direct Resource interface) which return standard pairs of pointers. mapped_file_resource file("hello.txt"); std::pair<char*, char*> seq = file.input_sequence(); char* ptr = seq.first; size_t size = seq.second - seq.first; Hope this helps. Jonathan