C++ http proxy socket implementation

We are considering hiring an expert C++ developer to implement a socket function that accesses all IP's via an HTTP proxy (RFC7230). The function (prototype provided) has to connect to IP XXX port YYY via proxy PPP:HHH (if proxy != NULL), optionally with NTLMv2 auth (user+pwd) (if user != NULL) and return either with an error or with the final socket, connected to XXX:YYY. The function must handle all error conditions (via return code). The implementation must work on VisualStudio 2010 and following, and with Linux/gcc Please provide with your bid examples of your code, demonstrating TCP/IP and multiplatform coding skills. Header provided below: #define SS_HTTPPROXIED_OK 0 #define SS_HTTPPROXIED_xxx -1 // Add here error codes int ss_http_socket(SOCKET& *sock, int af, int type, int protocol, char *proxy = NULL, int port = 0, char *proxyUsername=NULL, char *proxyPassword=NULL);