如何做到使应用程序大地址感知？

问题描述

我目前正在进行我们的应用程序大地址感知。根据经验表明，这样做有一些意想不到的困境。我创建此帖子以制定需要执行的步骤的完整列表。

I am currently in process of making our application Large Address Aware. As experience has shown, there are some unexpected gotchas when doing so. I create this post to make a complete list of steps which need to be taken.

提供了一个很好的起点，但并不完整：

The development considerations listed in the AMD Large Address Aware guide provide a good starting point, but are by no means complete:

• 避免使用带符号的指针运算（即比较和添加）


• 指针使用所有32位。不要使用Bit31的东西。


• 某些dll将被加载在2GB边界下。


• 尽可能使用GlobalMemoryStatusEx（）（首选）或GlobalMemoryStatus（）来检索内存大小。

• Avoid the use of signed pointer arithmetic (I.e. compares and adds)
• Pointers use all 32-bits. Don’t use Bit31 for something else.
• Some dll’s will be loaded just under the 2GB boundary. In this case, no consecutive memory can be allocated with VirtualAlloc().
• Whenever possible, use GlobalMemoryStatusEx() (preferred) or GlobalMemoryStatus() to retrieve memory sizes.

因此，问题是：在制作C ++时需要做的事情的完整列表是什么Win32本机应用程序大地址感知？

推荐答案

• 在项目属性中的大于2千兆字节（/ LARGEADDRESSAWARE）：链接器/系统/启用大地址


• 检查所有指针减法并验证结果存储在可能包含可能差异的类型，或者用比较或其他结构替换它们 - 请参见 ）。注意：指针比较应该很好，与AMD的建议相反，没有理由为什么它应该导致4 GB的问题


• 确保你不假设指针有Bit31零，不要尝试


• 使用GetCursorInfo替换所有GetCursorPos调用 - 参见


• (obvious) select Support Address Larger than 2 Gigabytes (/LARGEADDRESSAWARE) in the project properties: Linker / System / Enable Large Address
• check all pointer subtractions and verify the result is stored in a type which can contain the possible difference, or replace them with comparisons or other constructs - see Detect pointer arithmetics because of LARGEADDRESSAWARE). Note: pointer comparison should be fine, contrary to AMD advice, there is no reason why it should cause 4 GB issues
• make sure you are not assuming pointers have Bit31 zero, do not attempt to use Bit31 for something else.
• replace all GetCursorPos calls with GetCursorInfo - see GetCursorPos fails with large addresses
• for all assignments into PVOID64 use PtrToPtr64, needed e.g. when using ReadFileScatter, see ReadFileScatter remark section

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