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Microsoft KB Archive/170426

From BetaArchive Wiki

PRB: VirtualProtect Limitations on Windows 95

Q170426



The information in this article applies to:


  • Microsoft Win32 Application Programming Interface (API), included with:
    • Microsoft Windows 95





SYMPTOMS

VirtualProtect() and VirtualProtectEx() functions fail with ERROR_INVALID_PARAMETER when you are setting access protection for a region of pages committed to a memory-mapped file.



CAUSE

VirtualProtect and VirtualProtectEx are not supported for memory that is mapped to the shared memory region (addresses between 2 GB and 3 GB), and the system memory regions (addresses between 3 GB and 4 GB). Since all memory-mapped files in Windows 95 are mapped to this region, the VirtualProtect functions are not supported for them.



STATUS

This behavior is by design.



MORE INFORMATION

NOTE: The VirtualProtect and VirtualProtectEx() functions may succeed under certain circumstances when attempting to set access protection to PAGE_READONLY or PAGE_NOACCESS for pages in the shared memory regions. This behavior should not be relied upon, and can cause other undesirable behavior.

Additional query words: VirtualProtect VirtualProtectEx Win95

Keywords : kbAPI kbKernBase kbGrpDSKernBase
Issue type : kbprb
Technology : kbAudDeveloper kbWin32sSearch kbWin32API


Last Reviewed: December 16, 2000
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