How can I use proxy in OpenSSL?

[user008]

Here is my connection code

int openConnection(const char *hostName, int port)
{
    struct hostent *host;
    struct sockaddr_in addr;
 
    if ((host = gethostbyname(hostName)) == nullptr) {
        perror(hostName);
        abort();
    }

    int sd = socket(PF_INET, SOCK_STREAM, 0);
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = *(long*)(host->h_addr);

    if (connect(sd, (struct sockaddr *)&addr, sizeof(addr)) != 0) {
        closesocket(sd);
        perror(hostName);
        abort();
    }

    return sd;
}

Where do I have to use this option?