WinSetHook

This function installs an application procedure into a specified hook chain.

Syntax

WinSetHook(hab, hmq, lHookType, pHookProc, Module)

Parameters

hab (HAB) - input

Anchor-block handle.

hmq (HMQ) - input

Queue identity.

This parameter identifies the queue to which the hook chain belongs. If hmq is set to NULLHANDLE, the hook is installed in the system hook chain. If hmq is set to HMQ_CURRENT, the hook is installed in the message queue associated with the current thread (calling thread).

lHookType (LONG) - input

Hook-chain type.

HK_CHECKMSGFILTER

       See CheckMsgFilterHook 

HK_CODEPAGECHANGED

       See CodePageChangedHook 

HK_DESTROYWINDOW

       See DestroyWindowHook 

HK_FINDWORD

       See FindWordHook 

HK_FLUSHBUF

       See FlushBufHook 

HK_HELP

       See HelpHook 

HK_INPUT

       See InputHook 

HK_JOURNALPLAYBACK

       See JournalPlaybackHook 

HK_JOURNALRECORD

       See JournalRecordHook 

HK_LOADER

       See LoaderHook 

HK_LOCKUP

       See LockupHook 

HK_MSGCONTROL

       See MsgControlHook

HK_MSGFILTER

       See MsgFilterHook 

HK_MSGINPUT

       See MsgInputHook 

HK_PLIST_ENTRY

       See ProgramListEntryHook 

HK_PLIST_EXIT

       See ProgramListExitHook 

HK_REGISTERUSERMSG

       See RegisterUserHook 

HK_SENDMSG

       See SendMsgHook 

HK_WINDOWDC

       See WindowDCHook 

pHookProc (PFN) - input

Address of the application hook procedure.

Module (HMODULE) - input

Resource identity.

Handle of the module that contains the application hook procedure, as returned by the DosLoadModule or DosQueryModuleHandle call. This parameter can be NULLHANDLE when a queue hook is being installed by an application into its own message queue.

When hooking a system hook this parameter must be a valid module handle.

Returns

rc (BOOL) - returns

Success indicator.

TRUE

Successful completion

FALSE

An error occurred.

Errors

Possible returns from WinGetLastError

PMERR_INVALID_HMQ (0x1002)

An invalid message-queue handle was specified.

PMERR_PARAMETER_OUT_OF_RANGE (0x1003)

The value of a parameter was not within the defined valid range for that parameter.

Remarks

Queue hooks are called before system hooks.

This function installs the hook at the head of either the system or queue chain. The most recently installed hook is called first.

Use the WinQueryWindowULong function to obtain the queue handle associated with a window handle.

Example Code

This example uses the WinSetHook call to intercept user-input messages from the application queue.

#define INCL_WINHOOKS
#include <OS2.H>
void RecordHook(HAB hab, PQMSG pqmsg);  /* prototype of hook */
                                        /* procedure.        */
samp()
{
HAB hab;
WinSetHook(hab,
          HMQ_CURRENT,
          HK_JOURNALRECORD,
          (PFN)RecordHook,
          (HMODULE)0); /* hook is into application queue. */

WinReleaseHook(hab,
              HMQ_CURRENT,
              HK_JOURNALRECORD,
              (PFN)RecordHook,
              (HMODULE)0); /* hook is into application queue, */

}
/*  This hook records user-input messages.  */
void RecordHook(HAB hab, PQMSG pqmsg)
{
   /*  ...   */
}

Definition

#define INCL_WINHOOKS /* Or use INCL_WIN, INCL_PM, */
#include <os2.h>

HAB        hab;        /*  Anchor-block handle. */
HMQ        hmq;        /*  Queue identity. */
LONG       lHookType;  /*  Hook-chain type. */
PFN        pHookProc;  /*  Address of the application hook procedure. */
HMODULE    Module;     /*  Resource identity. */
BOOL       rc;         /*  Success indicator. */

rc = WinSetHook(hab, hmq, lHookType, pHookProc, Module);

Related Functions

• WinCallMsgFilter
• WinReleaseHook