keyboard accellerator doesn't work.

[raleeper]

winmain calls creact to create the table and save the handle and this seems to work OK.

;   creact:   !CreateAccelTable   [achdl]  eax      retn

creact:
   invoke CreateAcceleratorTable,ADDR acceltbl,1

   or   eax, eax
     jnz   @F
   call   erbeep      ;debugging
@@:
   mov   [achdl], eax

   retn

The routine, located outside any procedure in "Global Utilities" is reached and the function does not fail.

This is the data used (in .DATA):

acceltbl   LABEL   BYTE
accel_k   LABEL   BYTE
   DB   FALT or FVIRTKEY
   DW   4Bh      ;keycode for k
   DW   21      ;CMD no. for alt-k
            ;acceltbl ends

achdl   DD   ?      ;ACcelerator table HanDLe


The winmain message loop is:

msglp:
   invoke   GetMessage, ADDR msg,NULL,0,0   ;msg local winmain

   or   eax, eax
     jz   msglp_ex
     js   msglp_err
   
   invoke   TranslateAccelerator, hwnd,achdl,ADDR msg

   or   eax, eax
     jz   @F
   call   erbeep      ;debugging

     jmp   msglp_dspch
@@:

   invoke   TranslateMessage, ADDR msg

msglp_dspch:
   invoke   DispatchMessage, ADDR msg

     jmp   msglp

The   invoke   TranslateAccelerator, hwnd,achdl,ADDR msg  always returns 0, and a WM_COMMAND message is never received.

Can anyone suggest what I am doing wrong?

The complete code is at:

http://www.intergate.com/~rale/lfw.asm

[MichaelW]

One problem is that the members of your ACCEL structure are not aligned as Windows expects. In the MASM32 windows.inc the structure is declared as:

Code Select Expand


ACCEL STRUCT WORD
  fVirt BYTE ?
  key   WORD ?
  cmd   WORD ?
ACCEL ENDS


The WORD alignment value specifies that the members should by aligned on 2-byte boundaries, so the offsets of the members from the start of the structure should be:

0 fVirt
2 key
4 cmd

But as you have defined it the offsets are:

0 fVirt
1 key
3 cmd

You can correct the problem by adding a 1-byte pad between the fVirt and key members, or by using the structure, something like this:

accel_tbl ACCEL <FALT or FVIRTKEY, 4bh, 21>

But note that this is may not be the only problem.

[raleeper]

Thank you.  It works now!

I've learned something about structures and alignment.

MichaelW
Global Moderator
Wrote:

   Re: keyboard accellerator doesn't work.
« Reply #1 on: Today at 09:35:37 AM »
   Reply with quote
One problem is that the members of your ACCEL structure are not aligned as Windows expects. In the MASM32 windows.inc the structure is declared as:

Code:
ACCEL STRUCT WORD
  fVirt BYTE ?
  key   WORD ?
  cmd   WORD ?
ACCEL ENDS

The WORD alignment value specifies that the members should by aligned on 2-byte boundaries, so the offsets of the members from the start of the structure should be:

0 fVirt
2 key
4 cmd

But as you have defined it the offsets are:

0 fVirt
1 key
3 cmd

You can correct the problem by adding a 1-byte pad between the fVirt and key members, or by using the structure, something like this:

accel_tbl ACCEL <FALT or FVIRTKEY, 4bh, 21>

But note that this is may not be the only problem.