This is the compilation error.
16:03:28 **** Build of configuration Sming for project Telnet_TCPServer_TCPClient ****
make all
LD out/build/app.out
c:/Espressif/sming/Sming/compiler/lib/\libsming.a(CommandOutput.o): In function `CommandOutput::~CommandOutput()':
C:\Espressif\sming\Sming/Services/CommandProcessing/CommandOutput.cpp:23: undefined reference to `WebSocket::sendString(String const&)'
c:/Espressif/sming/Sming/compiler/lib/\libsming.a(CommandOutput.o): In function `CommandOutput::write(unsigned char)':
C:\Espressif\sming\Sming/Services/CommandProcessing/CommandOutput.cpp:23: undefined reference to `WebSocket::sendString(String const&)'
collect2.exe: error: ld returned 1 exit status
make: *** [out/build/app.out] Error 1
16:03:31 Build Finished (took 2s.558ms)