windows - Secure Socket Connections using c++ -

i trying ssl/tls connections work in windows. right using schannel, not sure correct way go it. here code. exception thrown @ initializesecuritycontexta() function

#include "windows.h" #pragma comment(lib, "ws2_32.lib") #define security_win32 #include <schannel.h> #include <security.h>  int callback winmain(hinstance currentinstance, hinstance previousinstance, lpstr bs1, int bs2) {      // initialize winsock 2.0         wsadata versioninfo;         wsastartup (0x0202, &versioninfo);      // load security dll         hmodule securitydllmodule = loadlibrary("secur32.dll");      // initialize schannel         init_security_interface initsecurtyinterfacefunction = (init_security_interface)getprocaddress(securitydllmodule, "initsecurityinterfacea");         psecurityfunctiontable schannel = initsecurtyinterfacefunction();         if (!schannel)             messagebox(0, "failed initialize schannel", "message", mb_taskmodal | mb_ok);         else             messagebox(0, "initialized schannel", "message", mb_taskmodal | mb_ok);      // setup schannel credentials         dword protocol = sp_prot_tls1;         schannel_cred schannelcredentials;         zeromemory(&schannelcredentials, sizeof(schannelcredentials));         schannelcredentials.dwversion = schannel_cred_version;         schannelcredentials.grbitenabledprotocols = protocol;         schannelcredentials.dwflags |= sch_cred_no_default_creds;         schannelcredentials.dwflags |= sch_cred_manual_cred_validation;      // client credentials handle         credhandle clientcredentials;         security_status securitystatus = schannel->acquirecredentialshandlea(             0,              unisp_name_a,             secpkg_cred_outbound,             0,             &schannelcredentials,             0,             0,             &clientcredentials,             0         );                   if (securitystatus != sec_e_ok)             messagebox(0, "failed credenetials", "message", mb_taskmodal | mb_ok);         else             messagebox(0, "got client credenetials", "message", mb_taskmodal | mb_ok);      // connect google         socket mysocket = socket(pf_inet, sock_stream, 0);         sockaddr_in sin;         sin.sin_family = af_inet;         sin.sin_port = htons(443);         hostent *hp = gethostbyname("www.google.com");         memcpy(&sin.sin_addr, hp->h_addr, 4);         if (connect(mysocket, (struct sockaddr *)&sin, sizeof(sin)) == socket_error)             messagebox(0, "error connecting", "message", mb_taskmodal | mb_ok);         else             messagebox(0, "connected", "message", mb_taskmodal | mb_ok);      // perform handshake:         dword sspiflags = (             isc_req_sequence_detect             | isc_req_replay_detect             | isc_req_confidentiality             | isc_ret_extended_error             | isc_req_allocate_memory             | isc_req_stream         );          secbuffer outbuffers[1];         outbuffers[0].pvbuffer = 0;         outbuffers[0].buffertype = secbuffer_token;         outbuffers[0].cbbuffer = 0;          secbufferdesc outbuffer;         outbuffer.cbuffers = 1;         outbuffer.pbuffers = outbuffers;         outbuffer.ulversion = secbuffer_version;          dword sspioutflags;         ctxthandle* contexthandle;         security_status scret = schannel->initializesecuritycontexta(             &clientcredentials,             0,             "www.google.com",             sspiflags,             0,             security_native_drep,             0,             0,             contexthandle,             &outbuffer,             &sspioutflags,             0         );         if (scret != sec_i_continue_needed)             messagebox(0, "error initializing security context", "message", mb_taskmodal | mb_ok);         else             messagebox(0, "security context initialized", "message", mb_taskmodal | mb_ok);      // done         messagebox(0, "done", "message", mb_taskmodal | mb_ok);         return 0; } 

change ctxthandle* contexthandle; ctxthandle contexthandle; , instead of contexthandle pass &contexthandle initializesecuritycontexta() call.