To create a connection, create an environment handle and a connection handle using SQLAllocHandle. You can then use SQLDriverConnect to provide a DSN or an ODBC connection string.

Connect to a DSN

  SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv); 
  SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0); 
  SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc); 
  SQLDriverConnect(hdbc, 0, (SQLCHAR*)"Dsn=Connect Source;", SQL_NTS, 0, 0, 0, 0);

Provide a Driver Connection String

  SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv); 
  SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0); 
  SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc); 
  SQLDriverConnect(hdbc, 0, (SQLCHAR*)"DRIVER={ODBC Driver for CData Connect};AuthScheme=basic;URL=http://hostname:port/rest.rsc;User=my_user;Password=my_password;", SQL_NTS, 0, 0, 0, 0);