How can I protect specific areas of memory with Win32 API?

Suppose I have a buffer of say 100 bytes as in char *pBuffer =开发者_如何学Go new char[100]; and I want to pass this to a third party function with specific instruction that it write into only the top half and that the bottom half is out of limits. How can I enforce that with Win32 API?

Thanks.

PS: This particular example might not be perfect but I am clear about my question.

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You'll need to use VirtualProtect to mark the last half as readonly. Since VirtualProtect works with pages, not bytes, you will in your example need to VirtualAlloc PAGE_SIZE + 50 bytes, and adjust pBuffer so it matches your requirements.