76 lines
2.2 KiB
Plaintext
76 lines
2.2 KiB
Plaintext
This document describes some points you should know before implementing
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the internal counterparts to external DLL's. Only 32 bit DLL's
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are considered.
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1. The LibMain function
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-----------------------
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This is the way to do some initializing when a process or thread is attached
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to the dll. The function name is taken from a *.spec file line:
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init YourFunctionName
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then, you have to implement the function:
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BOOL32 WINAPI YourLibMain(HINSTANCE32 hinstDLL,
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DWORD fdwReason, LPVOID lpvReserved)
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{ if (fdwReason==DLL_PROCESS_ATTACH)
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{ ...
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}
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....
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}
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2. Using functions from other built-in DLL's
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--------------------------------------------
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The problem here is, that you can't know if you have to call the function from
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the internal or the external DLL. If you just call the function you will get
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the internal implementation. If the external DLL is loaded the executed program
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will use the external DLL and you the internal one.
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When you -as an example- fill an iconlist placed in the internal DLL the
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application won't get the icons from the external DLL.
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To work around this, you should always use a pointer to call such functions:
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/* definition of the pointer type*/
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void (CALLBACK* pDLLInitComctl)();
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/* getting the function address this should be done in the
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LibMain function when called with DLL_PROCESS_ATTACH*/
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BOOL32 WINAPI Shell32LibMain(HINSTANCE32 hinstDLL, DWORD fdwReason,
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LPVOID lpvReserved)
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{ HINSTANCE32 hComctl32;
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if (fdwReason==DLL_PROCESS_ATTACH)
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{ /* load the external / internal DLL*/
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hComctl32 = LoadLibrary32A("COMCTL32.DLL");
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if (hComctl32)
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{ /* get the function pointer */
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pDLLInitComctl=GetProcAddress32(hComctl32,"InitCommonControlsEx");
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/* check it */
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if (pDLLInitComctl)
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{ /* use it */
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pDLLInitComctl();
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}
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/* free the DLL / decrease the ref count */
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FreeLibrary32(hComctl32);
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}
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else
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{ /* do some panic*/
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ERR(shell,"P A N I C error getting functionpointers\n");
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exit (1);
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}
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}
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....
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3. Getting resources from a *.rc file linked to the DLL
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-------------------------------------------------------
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< If you know how, write some lines>
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----------
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<juergen.schmied@metronet.de>
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