The Dx9 SDKs ddraw.lib is strange(to me). This is the exports from dumpbin:
Exports
ordinal name
_DDGetAttachedSurfaceLcl@12
_DDInternalLock@8
_DDInternalUnlock@4
_DSoundHelp@12
_DirectDrawCreate@12
_DirectDrawCreateClipper@12
_DirectDrawCreateEx@16
_DirectDrawEnumerateA@8
_DirectDrawEnumerateExA@12
_DirectDrawEnumerateExW@12
_DirectDrawEnumerateW@8
_GetDDSurfaceLocal@12
_GetSurfaceFromDC@12
Thats it. Older ones have full style __imp__DirectDrawCreate@12 and the above style.
Is there anything different/special about the above style?
I've been fooling around with making my own jump table for the windoes API:
I doing the above for a reason beyond the scope of this post. Lets just say it works great.
As I write this I decided to look at the disassem for a call to _DirectDrawCreate@12:
It seems it puts the jmp in my code section 0x401000, whereas the API jmp table starts from 0x403000. A different section alltogether. Its been a long time since I last used jmp tables. Is there any difference to the linker if you have:
_DirectDrawCreate@12
or
__imp__DirectDrawCreate@12
Assuming the symbols exist in the lib of course.
Thanks.
Exports
ordinal name
_DDGetAttachedSurfaceLcl@12
_DDInternalLock@8
_DDInternalUnlock@4
_DSoundHelp@12
_DirectDrawCreate@12
_DirectDrawCreateClipper@12
_DirectDrawCreateEx@16
_DirectDrawEnumerateA@8
_DirectDrawEnumerateExA@12
_DirectDrawEnumerateExW@12
_DirectDrawEnumerateW@8
_GetDDSurfaceLocal@12
_GetSurfaceFromDC@12
Thats it. Older ones have full style __imp__DirectDrawCreate@12 and the above style.
Is there anything different/special about the above style?
I've been fooling around with making my own jump table for the windoes API:
.data
JTBL TEXTEQU <dw 025ffh>;indirect jump
__imp__ExitProcess@4:
JTBL
dd offset _imp__ExitProcess@4
__imp__GetModuleHandleA@4:
JTBL
dd offset _imp__GetModuleHandleA@4
__imp__GetMessageA@16:
JTBL
dd offset _imp__GetMessageA@16
I doing the above for a reason beyond the scope of this post. Lets just say it works great.
As I write this I decided to look at the disassem for a call to _DirectDrawCreate@12:
DirectDrawCreate:
00401180 FF 25 00 20 40 00 jmp dword ptr [__imp__DirectDrawCreate@12 (402000h)]
It seems it puts the jmp in my code section 0x401000, whereas the API jmp table starts from 0x403000. A different section alltogether. Its been a long time since I last used jmp tables. Is there any difference to the linker if you have:
_DirectDrawCreate@12
or
__imp__DirectDrawCreate@12
Assuming the symbols exist in the lib of course.
Thanks.
The .LIB file created for C-style DLLs (such as the core API) contains both entries.
Kernel32.lib, for example, might contain the equivalent of:
The linker probably won't care, but your code will. You don't want to jump to data, and you don't want to treat code as data (indirect jumps specify a data address).
Kernel32.lib, for example, might contain the equivalent of:
.code
_GetCommandLine@0:
jmp [__imp__GetCommandLine@0]
.data
__imp__GetCommandLine@0 DWORD ? ; To be filled by linker
The linker probably won't care, but your code will. You don't want to jump to data, and you don't want to treat code as data (indirect jumps specify a data address).