first commit for openGauss connect odbc code

loadlib.h

@@ -0,0 +1,42 @@
+/* File:			loadlib.h
+ *
+ * Description:		See "loadlib.c"
+ *
+ * Comments:		See "readme.txt" for copyright and license information.
+ *
+ */
+
+#ifndef __LOADLIB_H__
+#define __LOADLIB_H__
+
+#include "psqlodbc.h"
+#ifdef	HAVE_LIBLTDL
+#include <ltdl.h>
+#else
+#ifdef	HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif /* HAVE_DLFCN_H */
+#endif /* HAVE_LIBLTDL */
+
+#include <stdlib.h>
+#ifdef  __cplusplus
+extern "C" {
+#endif
+
+#ifdef	_HANDLE_ENLIST_IN_DTC_
+RETCODE	CALL_EnlistInDtc(ConnectionClass *conn, void * pTra, int method);
+RETCODE	CALL_DtcOnDisconnect(ConnectionClass *);
+RETCODE	CALL_IsolateDtcConn(ConnectionClass *, BOOL);
+void	*CALL_GetTransactionObject(HRESULT *);
+void	CALL_ReleaseTransactionObject(void *);
+#endif /* _HANDLE_ENLIST_IN_DTC_ */
+void	CleanupDelayLoadedDLLs(void);
+#ifdef	WIN32
+HMODULE MODULE_load_from_psqlodbc_path(const char *module_name);
+void	AlreadyLoadedPsqlodbc(void);
+#endif /* WIN32 */
+
+#ifdef	__cplusplus
+}
+#endif
+#endif /* __LOADLIB_H__ */