Determining the Newline character for the environment a C++ program is being compiled on

How does one determine the environment newline¹ in C++? Google yields many results for C# and .NET but I didn't see any way to do it for non-CLI C++.

Additional info: I need to scan a const char* for the character(s).

¹By "environment newline" I mean \r\n on Windows, \n on Linux, and \r on Mac.