int para_connect(int, struct sockaddr_in *);
int send_buffer(int, const char *);
int send_bin_buffer(int, const char *, size_t);
-int send_va_buffer(int, const char *, ...);
+__printf_2_3 int send_va_buffer(int fd, const char *fmt, ...);
int recv_buffer(int fd, char *buf, size_t size);
int recv_bin_buffer(int fd, char *buf, size_t size);
int para_accept(int, void *addr, socklen_t size);