Hi Johan

May-05-95, Johan Siegers wrote to All:

 JS> Can anyone post a working example, of how to set a hook ?

 JS> My application is created by WinCreateStdWindow().
 JS> I tried both a hook in the current HMQ as a system hook, both after
 JS> examples in Borlands Help (with a HK_INPUT hook). All by
 JS> hookprocedure does is a single beep. I DO get the beeps, but my
 JS> applications crashes in an access violation.
 JS> Should I perhaps set the hook at a very specific point ?

The hook procedure must reside in a DLL.  The procedure will be called in
different process contexts, and DLLs are loaded into the memory area that
is present in all process contexts.


Here is a DLL I made to monitor keyboard and mouse activity by hooking into
the system queue.

SCRDLL.C  (for BCOS2 1.0)
qp
/\

#define INCL_DOS
#define INCL_WIN
#include 

#include "scrdll.h"

ULONG ulActivity;
HMODULE hmDll;


#pragma argsused
static int APIENTRY DllInputHook (HAB hab, QMSG *Qmsg, ULONG fs)
{
  switch (Qmsg->msg)
  {
    case WM_CHAR:
    case WM_MOUSEMOVE:
    case WM_BUTTON1DOWN:
    case WM_BUTTON2DOWN:
    case WM_BUTTON3DOWN:
      ulActivity++;
      break;
  }
  return FALSE;
}


/* should be called from application at startup */
BOOL EXPENTRY DllInit (HAB hab)
{
  BOOL rc;

  rc = DosQueryModuleHandle ("SCRDLL", &hmDll);
  if (rc)
    return FALSE;

  rc = WinSetHook (hab, NULLHANDLE, HK_INPUT, DllInputHook, hmDll);
  if (!rc)
    return FALSE;

  ulActivity = 0;
  return TRUE;
}


/* returns the amount of activity since last time */
ULONG EXPENTRY DllGetActivity (VOID)
{
  ULONG activity = ulActivity;

  ulActivity = 0;
  return activity;
}


/* should be called from the application before terminating */
BOOL EXPENTRY DllDeinit (HAB hab)
{
  BOOL rc;

  rc = WinReleaseHook (hab, NULLHANDLE, HK_INPUT, DllInputHook, hmDll);
  if (!rc)
    return FALSE;
  return TRUE;
}

\/
db


Regards, Karl

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