added close() to socketstream

libscio.hpp

@@ -149,6 +149,8 @@ namespace sc {
 
 				// cleanup: socketstream is RAII class for open socket
 				virtual ~socketstream();
+				bool is_open() { return _iobuf.fd() != -1; }
+				void close();
 
 				// server
 				void make_server(const socket_address& sa);

socketstream.cpp

@@ -53,8 +53,13 @@ socketstream& socketstream::operator=(socketstream&& other) {
 }
 
 socketstream::~socketstream() {
+	close();
+}
+
+void socketstream::close() {
 	if (_iobuf.fd() != -1) {
 		::close(_iobuf.fd());
+		_iobuf.fd(-1);
 	}
 }