==== MouRegister ====

**Bindings**: [[register#C bindings|C]], [[register#MASM bindings|MASM]]

This call registers a mouse subsystem within a session. 

//MouRegister// (ModuleName, EntryName, Mask) 

//ModuleName// (**PSZ**) - input 
Address of the dynamic link module name. The maximum length is 9 bytes (including ASCIIZ terminator). 

//EntryName// (**PSZ**) - input 
Address of the dynamic link entry point name of a routine that receives control when any of the registered functions are called. The maximum length is 33 bytes (including ASCIIZ terminator). 

//Mask// (**ULONG**) - input 
A mask of bits, where each bit set to 1 identifies a mouse function being registered. Bit values are: 

^Bit ^Description ^
|31-22 |Reserved, set to zero |
|21 |[[en:ibm:prcp:mou:setdevstatus|MouSetDevStatus]] |
|20 |[[en:ibm:prcp:mou:flushque|MouFlushQue]] |
|19 |[[en:ibm:prcp:mou:initreal|MouInitReal]] |
|18 |[[en:ibm:prcp:mou:setptrpos|MouSetPtrPos]] |
|17 |[[en:ibm:prcp:mou:getptrpos|MouGetPtrPos]] |
|16 |[[en:ibm:prcp:mou:removeptr|MouRemovePtr]] |
|15 |[[en:ibm:prcp:mou:drawptr|MouDrawPtr]] |
|14 |[[en:ibm:prcp:mou:setptrshape|MouSetPtrShape]] |
|13 |[[en:ibm:prcp:mou:getptrshape|MouGetPtrShape]] |
|12 |[[en:ibm:prcp:mou:close|MouClose]] |
|11 |[[en:ibm:prcp:mou:open|MouOpen]] |
|10 |Reserved |
|9 |Reserved |
|8 |[[en:ibm:prcp:mou:seteventmask|MouSetEventMask]] |
|7 |[[en:ibm:prcp:mou:setscalefact|MouSetScaleFact]] |
|6 |[[en:ibm:prcp:mou:geteventmask|MouGetEventMask]] |
|5 |[[en:ibm:prcp:mou:getscalefact|MouGetScaleFact]] |
|4 |[[en:ibm:prcp:mou:readeventque|MouReadEventQue]] |
|3 |[[en:ibm:prcp:mou:getnumqueel|MouGetNumQueEl]] |
|2 |[[en:ibm:prcp:mou:getdevstatus|MouGetDevStatus]] |
|1 |[[en:ibm:prcp:mou:getnummickeys|MouGetNumMickeys]] |
|0 |[[en:ibm:prcp:mou:getnumbuttons|MouGetNumButtons]] |

//rc// (**USHORT**) - return 
Return code descriptions are: 

|0 |NO_ERROR |
|385 |ERROR_MOUSE_NO_DEVICE |
|413 |ERROR_MOUSE_INVALID_ASCIIZ |
|414 |ERROR_MOUSE_INVALID_MASK |
|415 |ERROR_MOUSE_REGISTER |
|466 |ERROR_MOU_DETACHED |
|505 |ERROR_MOU_EXTENDED_SG |

**Remarks** 

The Base Mouse Subsystem is the default mouse subsystem. There can be only one [[en:ibm:prcp:mou:register|MouRegister]] outstanding for each session without an intervening [[en:ibm:prcp:mou:dereg|MouDeRegister]]. [[en:ibm:prcp:mou:dereg|MouDeRegister]] must be issued by the same process that issued [[en:ibm:prcp:mou:register|MouRegister]]. 

When any registered function is called, control is routed to //EntryName//. When this routine is entered, four additional values are pushed onto the stack. The first is the index number (Word) of the function being called. The second is a near pointer (Word). The third is the caller's DS register (Word). The fourth is the return address (DWord) to the mouse router. For example, if [[en:ibm:prcp:mou:getnummickeys|MouGetNumMickeys]] were called and control routed to //EntryName//, the stack would appear as if the following instructions were executed: 

<code asm>
PUSH@ WORD    NumberOfMickeys
PUSH  WORD    DeviceHandle
CALL  FAR     MouGetNumMickeys
PUSH  WORD    Function Code
CALL  NEAR    Entry point in Mouse Router
PUSH  DS       
CALL  FAR     EntryName.
</code>


When a registered function returns to the Mouse Router, AX is interpreted as follows: 

AX = 0 
No error. Do not invoke the Base Mouse Subsystem routine. Return AX = 0. 

AX = -1 
Invoke the BaseMouse Subsystem routine. Return AX = return code from the Base Mouse Subsystem. 

AX = error (if not 0 or -1) 
Do not invoke the Base Mouse Subsystem Routine. Return AX = error. 

When the mouse router receives a mouse call, it routes it to the Base Mouse Subsystem unless an application or other mouse subsystem has previously issued [[en:ibm:prcp:mou:register|MouRegister]] for that call. If the call was registered, the subsystem is entered at the //EntryName// specified, and provided with the applicable function code. 

The registered function mask is used to determine whether a requested function is performed by the registered mouse subsystem or default to the Base Mouse Subsystem. 

The following list shows the relationship of the mouse API calls and the Function Code passed to either the Base Mouse Subsystem or a registered mouse subsystem. 

^MOU API calls ^Function Code ^
|[[en:ibm:prcp:mou:getnumbuttons|MouGetNumButtons]] |00H |
|[[en:ibm:prcp:mou:getnummickeys|MouGetNumMickeys]] |01H |
|[[en:ibm:prcp:mou:getdevstatus|MouGetDevStatus]] |02H |
|[[en:ibm:prcp:mou:getnumqueel|MouGetNumQueEl]] |03H |
|[[en:ibm:prcp:mou:readeventque|MouReadEventQue]] |03H |
|[[en:ibm:prcp:mou:getscalefact|MouGetScaleFact]] |05H |
|[[en:ibm:prcp:mou:geteventmask|MouGetEventMask]] |06H |
|[[en:ibm:prcp:mou:setscalefact|MouSetScaleFact]] |07H |
|[[en:ibm:prcp:mou:seteventmask|MouSetEventMask]] |08H |
|Reserved |09H |
|Reserved |0AH |
|[[en:ibm:prcp:mou:open|MouOpen]] |0BH |
|[[en:ibm:prcp:mou:close|MouClose]] |0CH |
|[[en:ibm:prcp:mou:getptrshape|MouGetPtrShape]] |0DH |
|[[en:ibm:prcp:mou:setptrshape|MouSetPtrShape]] |0EH |
|[[en:ibm:prcp:mou:drawptr|MouDrawPtr]] |0FH |
|[[en:ibm:prcp:mou:removeptr|MouRemovePtr]] |10H |
|[[en:ibm:prcp:mou:getptrpos|MouGetPtrPos]] |11H |
|[[en:ibm:prcp:mou:setptrpos|MouSetPtrPos]] |12H |
|[[en:ibm:prcp:mou:initreal|MouInitReal]] |13H |
|[[en:ibm:prcp:mou:flushque|MouFlushQue]] |14H |
|[[en:ibm:prcp:mou:setdevstatus|MouSetDevStatus]] |15H |

A registered mouse sybsystem must leave the stack, on exit, in the exact state it was received. 

=== C bindings ===

<code c>
#define INCL_MOU

USHORT  rc = MouRegister(ModuleName, EntryName, Mask);

PSZ              ModuleName;    /* Module Name */
PSZ              EntryName;     /* Entry Name */
ULONG            Mask;          /* Function Mask */

USHORT           rc;            /* return code */
</code>

=== MASM bindings ===

<code asm>
EXTRN   MouRegister:FAR
INCL_MOU            EQU 1

PUSH@  ASCIIZ  ModuleName    ;Module Name
PUSH@  ASCIIZ  EntryName     ;Entry Name
PUSH   DWORD   Mask          ;Function Mask
CALL   MouRegister

Returns WORD
</code>