Pass std::strings by ref

src/zm_remote_camera_nvsocket.cpp

@@ -137,7 +137,7 @@ int RemoteCameraNVSocket::Disconnect() {
   return( 0 );
 }
 
-int RemoteCameraNVSocket::SendRequest( std::string request ) {
+int RemoteCameraNVSocket::SendRequest(const std::string &request) {
   //Debug( 4, "Sending request: %s", request.c_str() );
   if ( write( sd, request.data(), request.length() ) < 0 ) {
     Error( "Can't write: %s", strerror(errno) );

src/zm_remote_camera_nvsocket.h

@@ -51,7 +51,7 @@ public:
   void Terminate() override { Disconnect(); }
   int Connect() override;
   int Disconnect() override;
-  int SendRequest(std::string);
+  int SendRequest(const std::string &);
   int GetResponse();
   int PrimeCapture() override;
   int Capture(std::shared_ptr<ZMPacket> &p) override;