Invalid orincomplete multibyte or wide character

int main (int argc, char ** argv)

{

	int mysock;

	struct sockaddr_in myaddr ;

	char * erreur = "0";

	char * recv_data;

	char * send_data = argv[2];

	int port = (int)(argv[1]);

	if(argv[1] == "help" || argc < 3)

	{

		help();

	}

	else

	{

		myaddr.sin_family = AF_INET;

		myaddr.sin_addr.s_addr = INADDR_ANY;

		myaddr.sin_port = htons ( port );

		myaddr.sin_zero[8];



		if ((mysock = socket(AF_INET,SOCK_STREAM,0)) != -1)

		{

			int reUseAddress = 1 ;

			if (setsockopt(mysock,SOL_SOCKET,SO_REUSEADDR,(char *) &reUseAddress,sizeof(reUseAddress)) >= 0)

			{

				if((bind (mysock,( struct sockaddr * ) &myaddr,sizeof ( myaddr ))) == 0 )

				{

					if((connect (mysock, ( sockaddr * ) &myaddr, sizeof ( myaddr ))) == 0)

					{

						int nonBlockingIO = 0;

						if (ioctl(mysock,FIONBIO,&nonBlockingIO) == 0)

						{

							//send ( mysock, send_data, sizeof(send_data), 0 );

							write ( mysock, send_data, sizeof(send_data));

							//recv ( mysock, recv_data, sizeof(recv_data), 0 );

							read( mysock, recv_data, sizeof(recv_data));

							if(errno != 0)

							{

								erreur = strerror(errno);

							}

						}

						else

						{

							erreur = strerror(errno);

						}

					}

					else

					{

						erreur = strerror(errno);

					}

				}

				else

				{

					erreur = strerror(errno);

				}

			}

			else

			{

				erreur = strerror(errno);

			}

		}

		else

		{

			erreur = strerror(errno);

		}



		if(close(mysock) == -1 && erreur == 0)

		{

			erreur = strerror(errno);

		}

		if(erreur != 0)

		{

			printf("\nErreur : %s\n",erreur);

		}

		else

		{

			printf("Données envoyées : %s\n",send_data);

			printf("Données reçues : %c\n",recv_data);

		}

	}

}