The object of class wostream that represents the standard error stream oriented to wide characters (of type wchar_t). It corresponds to the C stream stderr. The standard error stream is a destination of characters determined by the environment. This destination may be shared by more than one standard object (such as wcout or wclog).
Object of a basic_ostream class, characters can be written to it either as formatted data using the insertion operator (operator<<) or as unformatted data, using member functions such as write.
Following is the declaration for std::wcrr.
extern basic_ostream<wchar_t> wcerr;
By default, wcerr is synchronized with stderr.
A program should not mix output operations on wcerr with output operations on cerr or clog (or with other narrow-oriented output operations on stderr): Once an output operation has been performed on either, the standard error stream acquires an orientation (either narrow or wide) that can only be safely changed by calling freopen on stderr..