VioRegister

Description

This call registers an alternate video subsystem within a session.

Syntax

 VioRegister

    (ModuleName, EntryPoint, FunctionMask1, FunctionMask2)

Parameters

ModuleName (PSZ) - input

Address of the ASCIIZ string containing the 1-8 character file name of the subsystem. The maximum length of the ASCIIZ string is 9 bytes including the terminating byte of zero. The module must be a dynamic link library but the name supplied must not include the .DLL extension.

EntryPoint (PSZ) - input

Address of the ASCIIZ name string containing the dynamic link entry point name of the routine in the subsystem to receive control when any of the registered functions is called. The maximum length of the ASCIIZ string is 33 bytes including the terminating byte of zero.

FunctionMask1 (ULONG) - input

A bit mask where each bit identifies a video function being registered. The bit definitions are shown below. The first word pushed onto the stack contains the high-order 16 bits of the function mask, and the second word contains the low-order 16 bits.

     BIT   REGISTERED FUNCTION         BIT   REGISTERED FUNCTION
    ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ-
     31    VioPrtScToggle              15    VioWrtCharStr
     30    VioEndPopUp                 14    VioWrtTTY
     29    VioPopUp                    13    VioWrtNCell
     28    VioSavRedrawUndo            12    VioWrtNAttr
     27    VioSavRedrawWait            11    VioWrtNChar
     26    VioScrUnLock                10    VioReadCellStr
     25    VioScrLock                  9     VioReadCharStr
     24    VioPrtSc                    8     VioShowBuf
     23    VioGetAnsi                  7     VioSetMode
     22    VioSetAnsi                  6     VioSetCurType
     21    VioScrollRt                 5     VioSetCurPos
     20    VioScrollLf                 4     VioGetPhysBuf
     19    VioScrollDn                 3     VioGetBuf
     18    VioScrollUp                 2     VioGetMode
     17    VioWrtCellStr               1     VioGetCurType
     16    VioWrtCharStrAtt            0     VioGetCurPos

FunctionMask2 (ULONG) - input

A bit mask where each bit identifies a video function being registered. The bit mask has the format shown below. The first word pushed onto the stack contains the high order 16 bits of the function mask, and the second word contains the low order 16 bits. Unused bits are reserved and must be set to zero.

 Bit         Description 
31-9     Reserved, set to zero 
8        VioSetState 
7        VioGetState 
6        VioSetFont 
5        VioGetCp 
4        VioSetCp 
3        VioGetConfig 
2        VioGetFont 
1        VioModeUndo 
0        VioModeWait

Return Code

rc (USHORT) - return

Return code descriptions are:

• 0 NO_ERROR
• 349 ERROR_VIO_INVALID_MASK
• 403 ERROR_VIO_INVALID_ASCIIZ
• 426 ERROR_VIO_REGISTER
• 430 ERROR_VIO_ILLEGAL_DURING_POPUP
• 465 ERROR_VIO_DETACHED
• 494 ERROR_VIO_EXTENDED_SG

Remarks

An alternate video subsystem must register which video calls it handles. The default OS/2 video subsystem is the Base Video Subsystem.

When any of the registered functions are called, control is routed to EntryPoint. When this routine is entered, four additional values (5 words) are pushed onto the stack.

The first value is the index number (Word) of the routine being called. The second value is a near pointer (Word). The third value is the caller'sDSregister( Word ) . Thefourthvalueisthereturnaddress( DWord )totheVIOrouter .

For example, if VioSetCurPos were a registered function, the stack would appear as if the following instruction sequence were executed if VioSetCurPos were called and control routed to EntryPoint:

ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ PUSH     WORD     Row                                 ³
³ PUSH     WORD     Column                              ³
³ PUSH     WORD     VioHandle                           ³
³ CALL     FAR      VioSetCurPos                        ³
³ PUSH     WORD     Index                               ³
³ CALL     NEAR     Entry point in Vio router           ³
³ PUSH     WORD     Caller's DS                         ³
³ CALL     FAR      Dynamic link entry point            ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ

The index numbers that correspond to the registered functions are listed below:

VioGetPhysBuf

    22 VioSetAnsi 

1 VioGetBuf

    23 VioGetAnsi 

2 VioShowBuf

    24 VioPrtSc 

3 VioGetCurPos

    25 VioScrLock 

4 VioGetCurType

    26 VioScrUnLock 

5 VioGetMode

    27 VioSavRedrawWait 

6 VioSetCurPos

    28 VioSavRedrawUndo 

7 VioSetCurType

    29 VioPopUp 

8 VioSetMode

    30 VioEndPopUp 

9 VioReadCharStr

    31 VioPrtScToggle 

10 VioReadCellStr

    32 VioModeWait 

11 VioWrtNChar

    33 VioModeUndo 

12 VioWrtNAttr

    34 VioGetFont 

13 VioWrtNCell

    35 VioGetConfig 

14 VioWrtCharStr

    36 VioSetCp 

15 VioWrtCharStrAtt

    37 VioGetCp 

16 VioWrtCellStr

    38 VioSetFont 

17 VioWrtTTY

    39 VioGetState 

18 VioScrollUp

    40 VioSetState 

19 VioScrollDn

20 VioScrollLf

21 VioScrollRt

When a registered function returns to the video router, the return code is interpreted as follows:

Return code = 0

No error. Do not invoke the corresponding Base Video Subsystem routine. Return to caller with Return code = 0.

Return code = -1

No error. Invoke the corresponding Base Video Subsystem routine. Return to caller with Return code = return code from Base Video Subsystem.

Return code = error (not 0 or -1)

Do not invoke the corresponding Base Video Subsystem routine. Return to caller with Return code = error.

When an application registers a replacement for VioPopUp within a session, the registered routine is only invoked when that session is in the foreground. If VioPopUp is issued when that session is in the background, the OS/2 default routine is invoked.

An alternate video subsystem should be designed so the routines registered do not cause any hard errors when they are invoked. Otherwise, a system lockout occurs. Code and data segments of registered routines, that might be loaded from diskette, must be preloaded.

All VIO functions within a session are serialized on a thread basis. That is, when an alternate video subsystem receives control, it can safely assume that it is not called again from the same session until the current call has completed.