error_from_errno

Gets a FileError constant based on the passed-in err_no.

For example, if you pass in `EEXIST` this function returns g_file_error_exist. Unlike `errno` values, you can portably assume that all FileError values will exist.

Normally a FileError value goes into a Error returned from a function that manipulates files. So you would use error_from_errno when constructing a Error.

Parameters:

err_no

an "errno" value

Returns:

FileError corresponding to the given err_no