Portable file I/O with system error codes support
Hi, I'm looking for a portable way to open a file, read some data from it, and do a proper error reporting in case of error. Apparently std::fstream is not suitable for this task because it does not provide means to retrieve original error code or even some human readable description of what went wrong (checking errno does not count since the standard does not guarantee it is set by any functions in std::fstream). I'm wondering if boost::iostreams can do that, but I've found nothing this far that could help in getting the error code. I've also tried boost::filesystem::fstream, but no luck. Users of large frameworks like Qt have advantage of their portable wrappers for file I/O like QFile. Are there any means in Boost which provide similar functionality? Related StackOverflow question: https://stackoverflow.com/questions/45840686/portable-way-to-read-a-file-in-... Thanks.
Beast has a cross platform File API: http://www.boost.org/doc/libs/develop/libs/beast/doc/html/beast/using_io/fil... -- Follow me on GitHub: https://github.com/vinniefalco
I'm looking for a portable way to open a file, read some data from it, and do a proper error reporting in case of error.
Literally https://ned14.github.io/afio/index.html It's the post Boost peer review design after a peer review here in August 2015. It looks to have some legs as part of a future C++ standardised replacement i/o layer for iostreams, Intel just very kindly made available to me their Optane storage devices so I can tune AFIO v2 for them. I am currently (re)porting AFIO to FreeBSD and libc++ specifically for the Optane trials.
Apparently std::fstream is not suitable for this task because it does not provide means to retrieve original error code or even some human readable description of what went wrong (checking errno does not count since the standard does not guarantee it is set by any functions in std::fstream).
The original error code is preserved on all platforms. So, on Windows, that's the NT kernel error code if a NT kernel function was used. You can use the C++ 11 STL mechanism of error conditions to compare the original error code against any std::errc::* generic error condition, and apart from bugs some of which stem from Microsoft's incorrect mapping, it should work. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/
participants (3)
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Niall Douglas -
Oleg Andriyanov -
Vinnie Falco