...
#include "ezbztlsc.h"               /* SIOCTTLSCTL ioctl             */
...
  struct TTLS_IOCTL ioc;            /* ioctl data structure          */
  char buff[1000];                  /* buffer for certificate        */
...
  /* issue the SIOCTTLSCTL ioctl */
  memset(&ioc,0,sizeof(ioc));       /* set all unused fields to zero */ 
  ioc.TTLSi_Ver = TTLS_VERSION1;
  ioc.TTLSi_Req_Type = TTLS_INIT_CONNECTION | TTLS_RETURN_CERTIFICATE;
  ioc.TTLSi_BufferPtr = &buff
  ioc.TTLSi_BufferLen = sizeof(buff);

  rc = ioctl(s,SIOCTTLSCTL,(char *)&ioc);
  if (rc < 0)
  {
    /* do failure logic. If the socket is in non-      */
    /* blocking mode then you may also receive rc      */
    /* of -1 with an errno of EINPROGRESS. This does   */
    /* not indicate an error. Wait for the completion  */
    /* of the handshake with select() for WRITEABLE.   */
  }