"HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org"> extern cppreference.com > "index.html">C/C++ Keywords > "extern.html">extern extern The extern keyword is used to inform the compiler about variables declared outside of the current scope. Variables described by extern statements will not have any space allocated for them, as they should be properly defined elsewhere. Extern statements are frequently used to allow data to span the scope of multiple files.
