A portable C++ 11 STL std::error_category implementation for the NT kernel error code space i.e. NTSTATUS. Implemented at ntkernel_error_category::ntkernel_category().

Features:

• Provides a complete set of string messages for the system facility, as according to Microsoft Windows 10, for the warning and error categories. Note that the strings are in US English only.
• Implements mapped comparisons to error conditions of std::system_category on Windows (i.e. the GetLastError() error code space).
• Implements mapped comparisons to error conditions of std::generic_category on all platforms (i.e. the POSIX errno error code space).
• Comes in three implementation variants:
  • Header-only table (NTKERNEL_ERROR_CATEGORY_INLINE=1).
  • Static library table (NTKERNEL_ERROR_CATEGORY_STATIC=1).
  • Shared library table (the default).

The default of NTKERNEL_ERROR_CATEGORY_STATIC and NTKERNEL_ERROR_CATEGORY_INLINE both NOT being defined means that the shared library table is the default. As std::error_category instances must be globally unique in a process as per the C++ standard, this form - despite its inconvenience - is the only standards conforming one. Any other setting may lead to more than one instance of the singleton, this can cause misoperation especially during error condition comparisons.