CallHook hook

From comp.os.os2.programmer.misc:

I recently came across this interesting bit of information (in "OS/2 for PowerPC API Addendum, of all places):

/*******************************************/ /* This hook is called for debugging      */ /* purposes, whenever any other hook      */ /* procedure is about to be called. */ /*******************************************/ HMQ     Current;   /* Message-queue handle associated with the current thread. */ HMQ     Created;   /* Message-queue handle created by the installing thread. */ PID     Pid;       /* Process identity of the installing thread. */ TID     Tid;       /* Thread identity of the installing thread. */ SHORT   HookType;  /* Hook type. */ PROC    HookProc;  /* Address of the hook procedure that is about to be called. */ BOOL    f;         /* Indicates whether or not the hook HookProc should be called: */ f = CallHook(Current, Created, Pid, Tid, HookType, HookProc);
 * 1) define INCL_xxx
 * 2) include 

I could really use this function. I have just one little problem, I have no idea what the HK_ constant for this one might be. Before I resort to trial & error, does anyone know what the constant might be?

And just in case someone thinks this was OS/2 PPC specific, there is a symbol called CALLCALLHOOKHOOK in PMWIN.SYM (at least some old version of PMWIN.SYM) along with CALLINPUTHOOK, CALLSENDMSGHOOK etc. so I'm almost certain this functionality has been in OS/2 for quite a while.

Answer:
 * 1) define HK_CALLHOOK                13