categories and standard/system error codes
I have to admit to a bit of surprise at the confusion regarding <system_error> given Chris summarised exactly how it works at http://blog.think-async.com/2010/04/system-error-support-in-c0x-part-1.html and I personally find the C++ standard text above perfectly clear. But to summarise in very succinct words: If on POSIX: generic_category => POSIX standard errno space system_category => Local POSIX errno …