SSLClient.cpp

//============================================================================
// Name        : SSLClient.cpp
// Compiling   : g++ -c -o SSLClient.o SSLClient.cpp
		 g++ -o SSLClient SSLClient.o -lssl -lcrypto
//============================================================================
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
using namespace std;

SSL *ssl;
int sock;

int RecvPacket()
{
	int len=100;
	char buf[1000000];
	do {
		len=SSL_read(ssl, buf, 100);
		buf[len]=0;
		printf(buf);
	} while (len > 0);
	if (len < 0) {
		int err = SSL_get_error(ssl, len);
		if (err == SSL_ERROR_WANT_READ)
			return 0;
		if (err == SSL_ERROR_WANT_WRITE)
			return 0;
		if (err == SSL_ERROR_ZERO_RETURN || err == SSL_ERROR_SYSCALL || err == SSL_ERROR_SSL)
			return -1;
	}
}

int SendPacket(const char *buf)
{
	int len = SSL_write(ssl, buf, strlen(buf));
	if (len < 0) {
		int err = SSL_get_error(ssl, len);
		switch (err) {
		case SSL_ERROR_WANT_WRITE:
			return 0;
		case SSL_ERROR_WANT_READ:
			return 0;
		case SSL_ERROR_ZERO_RETURN:
		case SSL_ERROR_SYSCALL:
		case SSL_ERROR_SSL:
		default:
			return -1;
		}
	}
}


void log_ssl()
{
	int err;
	while (err = ERR_get_error()) {
		char *str = ERR_error_string(err, 0);
		if (!str)
			return;
		printf(str);
		printf("\n");
		fflush(stdout);
	}
}


int main(int argc, char *argv[])
{
	int s;
	s = socket(AF_INET, SOCK_STREAM, 0);
	if (!s) {
		printf("Error creating socket.\n");
		return -1;
	}
	struct sockaddr_in sa;
	memset (&sa, 0, sizeof(sa));
	sa.sin_family      = AF_INET;
	sa.sin_addr.s_addr = inet_addr("74.125.232.247"); // address of google.ru
	sa.sin_port        = htons (443); 
	socklen_t socklen = sizeof(sa);
	if (connect(s, (struct sockaddr *)&sa, socklen)) {
		printf("Error connecting to server.\n");
		return -1;
	}
	SSL_library_init();
	SSLeay_add_ssl_algorithms();
	SSL_load_error_strings();
	const SSL_METHOD *meth = TLSv1_2_client_method();
	SSL_CTX *ctx = SSL_CTX_new (meth);
	ssl = SSL_new (ctx);
	if (!ssl) {
		printf("Error creating SSL.\n");
		log_ssl();
		return -1;
	}
	sock = SSL_get_fd(ssl);
	SSL_set_fd(ssl, s);
	int err = SSL_connect(ssl);
	if (err <= 0) {
		printf("Error creating SSL connection.	err=%x\n", err);
		log_ssl();
		fflush(stdout);
		return -1;
	}
	printf ("SSL connection using %s\n", SSL_get_cipher (ssl));

	char *request = "GET https://www.google.ru/intl/en/about/company/facts/ HTTP/1.1\r\n\r\n";
	SendPacket(request);
	RecvPacket();
	return 0;
}

Thanks for your code, it runs smoothly on windows with only a little modifications。Thanks...
But it would be better if you add resources free operations, the socket, ssl and ctx！
Best Wishes!

  starnight

does the code check the certificate? or you just skip the check .