HP NonStop G-Series - Manual (Page 118)

User Hook Library
Extending the Tandem DDE Gateway
8–16 110838 Tandem Computers Incorporated
TdmgwHookPreSendMessage
This function may be called when your client application does a DDE Execute function
with a SEND command.
You must enable the function with TdmgwHookEnableUserHooks function by
returning a value with the TDMGW_HOOK_ENABLE_PRE_SEND_MSG bit set.
The function is called immediately before the request message is sent to the Tandem
server.
Prototype
BOOL FAR PASCAL TdmgwHookPreSendMessage
(HWND hMainWnd, in
unsigned long ulInitializeServiceSerialNumber, in
LPSTR lpServiceName, in
char far * lpBufferStartAddress, in/out
unsigned int uBufferLength, in
unsigned int uSendLength, in
struct tagTdmgwErrorMsg far * pstructErrMsg); out
Parameters
Return Value Zero = Error.
Non-zero = No error.
hMainWnd Window handle of Tandem DDE Gateway main
window.
ulInitializeServiceSerialNumber Number incremented with each
INITIALIZESERVICE command. Starts at zero
when the Tandem DDE Gateway is started. Rolls
over to zero after 4,294,967,295.
lpServiceName Current ServiceName object (from
INITIALIZESERVICE command).
lpBufferStartAddress Address of start of the message buffer containing
the message data exactly as it will be sent to the
Tandem server.
uBufferLength Length of the message buffer as configured for the
ServiceName object (MaxSendLength attribute).
uSendLength Actual number of bytes sent to the Tandem server.
See DDE Execute function SEND command.
pstructErrMsg See “Returning Error Messages” earlier in this
section.
TdmgwHookUmsPostReceiveMessage
This function is called immediately after the UMS message is received by the Tandem
DDE Gateway.