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[BUG/PRB.] VFP 9.0 FIX - DO FORM COMMAND
January 2023
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CCB
1. BUG:
In vfp9, if we use the DO FORM command in the ON SELECTION BAR statement, sometimes VFP will crash.
The bug only occurs in vfp9 sp2, it does not occur in vfp6, vfp7, vfp8 and vfp9 sp1.
The bug occurs in the following commands:
ON BAR command
ON ERROR command
ON ESCAPE command
ON EXIT BAR command
ON EXIT MENU command
ON EXIT PAD command
ON EXIT POPUP command
ON KEY command
ON KEY LABEL command
ON PAD command
ON PAGE command
ON READERROR command
ON SELECTION BAR command
ON SELECTION MENU command
ON SELECTION PAD command
ON SELECTION POPUP command
ON SHUTDOWN command
2. CAUSE:
There are some BUGs in the following code.
3. RESOLUTION:
We can write some code to fix the BUG.
Label49c145 ::
mov esi , dword ptr [ Data93e6f0 ] ;0x0049c145 : 8b35f0e69300
test esi , esi ;0x0049c14b : 85f6
je Label49c17a ;0x0049c14d : 742b
;
; -------------------------------------------------
; VFP 9.0 FIX - DO FORM COMMAND
; November 2017
; -------------------------------------------------
; CCB
;
; If we use the DO FORM command in the ON SELECTION BAR statement, sometimes VFP will crash.
;
; 2017/11/30, by ccb
;
cmp dword ptr vfpa_sys9112_data,00h
je Label49c14f
mov eax , dword ptr [esi]
cmp dword ptr [eax] , 00h
jge Label49c158
cmp dword ptr [ eax + 12 ] , 00h
je Label49c17a
Label49c14f ::
call Fun54977a ;0x0049c14f : e826d60a00
test eax , eax ;0x0049c154 : 85c0
je Label49c17a ;0x0049c156 : 7422
Label49c158 ::
mov eax , dword ptr [ Data93e6f0 ] ;0x0049c158 : a1f0e69300
mov ecx , dword ptr [eax] ;0x0049c15d : 8b08
mov ecx , dword ptr [ecx] ;0x0049c15f : 8b09
lea eax , dword ptr [ ebp - 24 ] ;0x0049c161 : 8d45e8
call Fun41975b ;0x0049c164 : e8f2d5f7ff
push edi ;0x0049c169 : 57
lea edi , dword ptr [ ebp - 24 ] ;0x0049c16a : 8d7de8
call Fun433e2f ;0x0049c16d : e8bd7cf9ff
test eax , eax ;0x0049c172 : 85c0
jne Label5b7616 ;0x0049c174 : 0f859cb41100
Label49c17a ::
mov eax , dword ptr [ ebp - 32 ] ;0x0049c17a : 8b45e0
test eax , eax ;0x0049c17d : 85c0
mov edi , dword ptr [ ebp + 0108h ] ;0x0049c17f : 8bbd08010000
mov ebx , dword ptr [ ebp + 0110h ] ;0x0049c185 : 8b9d10010000
je Label5098c3 ;0x0049c18b : 0f8432d70600
mov edx , ebx ;0x0049c191 : 8bd3
mov byte ptr [ ebp - 28 ] , 050h ;0x0049c193 : c645e450
mov dword ptr [edx] , offset Data93d5c0 ;0x0049c197 : c702c0d59300
jmp Label5098c3 ;0x0049c19d : e921d70600
4. APPLIES TO:
VFP 9.0.0.4611 (SP2)
VFP 9.0.0.5015 (SP2)
VFP 9.0.0.5411 (SP2)
VFP 9.0.0.5721 (SP2)
VFP 9.0.0.5815 (SP2)
VFP 9.0.0.6303 (SP2)
VFP 9.0.0.6602 (SP2)
VFP 9.0.0.7423 (SP2)
The bug has been fixed in VFP Advanced.
5. REFERENCE WEBSITES:
1, baiyujia.com:
http://www.baiyujia.com
http://www.baiyujia.com/vfpdocuments/f_vfp9fix230.asp
2, foxite.com:
https://www.foxite.com/archives/another-vfp9-sp2-bug-0000150951.htm
6. OTHER:
For reference only, there is no guarantees.
Any questions or suggestions, please send me an email at ccb2000@163.com.
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