:mod:`uerrno` -- system error codes
===================================

.. module:: uerrno
   :synopsis: system error codes

This module provides access to symbolic error codes for `OSError` exception. 
``uerrno`` supports a subset of the functionality of the CPython ``errno`` module.

Constants
---------

.. data:: EEXIST, EAGAIN, etc.

    Error codes, based on ANSI C/POSIX standard. All error codes start with
    "E". Errors are usually accessible as ``exc.args[0]``
    where `exc` is an instance of `OSError`. Usage example::

        import uos
        try:
            uos.mkdir("my_dir")
        except OSError as exc:
            if exc.args[0] == uerrno.EEXIST:
                print("Directory already exists")

.. data:: errorcode

    Dictionary mapping numeric error codes to strings with symbolic error
    code (see above)::

        >>> print(uerrno.errorcode[uerrno.EEXIST])
        EEXIST