printf() and puts() wrappers for file descriptors

void sockputs(char* str, int sock) {
        write(sock, str, strlen(str));
}
void sockprintf(int sock, const char *format, ...) {
        //basically GNU asprintf
        const unsigned buf_size = 16;
        char* buf = (char*) malloc(sizeof(char) * buf_size);

        va_list vl;

    //first, try to vsnprintf to a buffer of length 16
        va_start(vl, format);
        unsigned len = vsnprintf(buf, buf_size, format, vl);
        va_end(vl);

    //if that wasn't enough, allocate more memory and try again
        if (len >= buf_size) {
                buf = (char*) realloc(buf, sizeof(char) * (len + 1));
                va_start(vl, format);
                vsnprintf(buf, len + 1, format, vl);
                va_end(vl);
        }

        //output buf to the socket
        sockputs(buf, sock);

        //free the buffer
        free(buf);
}