39 lines
1.3 KiB
Plaintext
39 lines
1.3 KiB
Plaintext
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Some notes concerning accelerators.
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There are _three_ differently sized accelerator structures exposed to the
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user. The general layout is:
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BYTE fVirt;
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WORD key;
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WORD cmd;
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We now have three different appearances:
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- Accelerators in NE resources. These have a size of 5 byte and do not have
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any padding. This is also the internal layout of the global handle HACCEL
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(16 and 32) in Windows 95 and WINE. Exposed to the user as Win16 global
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handles HACCEL16 and HACCEL32 by the Win16/Win32 API.
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- Accelerators in PE resources. These have a size of 8 byte. Layout is:
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BYTE fVirt;
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BYTE pad0;
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WORD key;
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WORD cmd;
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WORD pad1;
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They are exposed to the user only by direct accessing PE resources.
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- Accelerators in the Win32 API. These have a size of 6 byte. Layout is:
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BYTE fVirt;
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BYTE pad0;
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WORD key;
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WORD cmd;
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These are exposed to the user by the CopyAcceleratorTable and
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CreateAcceleratorTable in the Win32 API.
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Why two types of accelerators in the Win32 API? We can only guess, but
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my best bet is that the Win32 resource compiler can/does not handle struct
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packing. Win32 ACCEL is defined using #pragma(2) for the compiler but without
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any packing for RC, so it will assume #pragma(4).
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Findings researched by Uwe Bonnes, Ulrich Weigand and Marcus Meissner.
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