FS#150 - SFML should use its own stream instead of std::cerr, for reporting errors

git-svn-id: https://sfml.svn.sourceforge.net/svnroot/sfml/branches/sfml2@1417 4e206d99-4929-0410-ac5d-dfc041789085

include/SFML/System/Err.hpp

@@ -0,0 +1,77 @@
+////////////////////////////////////////////////////////////
+//
+// SFML - Simple and Fast Multimedia Library
+// Copyright (C) 2007-2009 Laurent Gomila (laurent.gom@gmail.com)
+//
+// This software is provided 'as-is', without any express or implied warranty.
+// In no event will the authors be held liable for any damages arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it freely,
+// subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented;
+//    you must not claim that you wrote the original software.
+//    If you use this software in a product, an acknowledgment
+//    in the product documentation would be appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such,
+//    and must not be misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source distribution.
+//
+////////////////////////////////////////////////////////////
+
+#ifndef SFML_ERR_HPP
+#define SFML_ERR_HPP
+
+////////////////////////////////////////////////////////////
+// Headers
+////////////////////////////////////////////////////////////
+#include <SFML/Config.hpp>
+#include <ostream>
+
+
+namespace sf
+{
+////////////////////////////////////////////////////////////
+/// \brief Standard stream used by SFML to output warnings and errors
+///
+////////////////////////////////////////////////////////////
+SFML_API std::ostream& Err();
+
+} // namespace sf
+
+
+#endif // SFML_ERR_HPP
+
+
+////////////////////////////////////////////////////////////
+/// \fn sf::Err
+///
+/// By default, sf::Err() outputs to the same location as std::cerr,
+/// (-> the stderr descriptor) which is the console if there's
+/// one available.
+///
+/// It is a standard std::ostream instance, so it supports all the
+/// insertion operations defined by the STL
+/// (operator <<, manipulators, etc.).
+///
+/// sf::Err() can be redirected to write to another output, independantly
+/// of std::cerr, by using the rdbuf() function provided by the
+/// std::ostream class.
+///
+/// Example:
+/// \code
+/// // Redirect to a file
+/// std::ofstream file("sfml-log.txt");
+/// std::streambuf* previous = sf::Err().rdbuf(file.rdbuf());
+///
+/// // Redirect to nothing
+/// sf::Err().rdbuf(NULL);
+///
+/// // Restore the original output
+/// sf::Err().rdbuf(previous);
+/// \endcode
+///
+////////////////////////////////////////////////////////////