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siphonelee 2002-09-27
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分页内存的问题
如果不锁定
将可能不在内存
而被移动到虚存即硬盘上
如果不锁定
将可能不在内存
而被移动到虚存即硬盘上
oldworm 2002-09-27
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GlobalLock函数，MSDN是这样解释的：
The internal data structures for each memory object include a lock count that is initially zero. For movable memory objects, GlobalLock increments the count by one, and the GlobalUnlock function decrements the count by one. For each call that a process makes to GlobalLock for an object, it must eventually call GlobalUnlock. Locked memory will not be moved or discarded, unless the memory object is reallocated by using the GlobalReAlloc function. The memory block of a locked memory object remains locked until its lock count is decremented to zero, at which time it can be moved or discarded.
Memory objects allocated with GMEM_FIXED always have a lock count of zero. For these objects, the value of the returned pointer is equal to the value of the specified handle.
If the specified memory block has been discarded or if the memory block has a zero-byte size, this function returns NULL.
Discarded objects always have a lock count of zero.
The internal data structures for each memory object include a lock count that is initially zero. For movable memory objects, GlobalLock increments the count by one, and the GlobalUnlock function decrements the count by one. For each call that a process makes to GlobalLock for an object, it must eventually call GlobalUnlock. Locked memory will not be moved or discarded, unless the memory object is reallocated by using the GlobalReAlloc function. The memory block of a locked memory object remains locked until its lock count is decremented to zero, at which time it can be moved or discarded.
Memory objects allocated with GMEM_FIXED always have a lock count of zero. For these objects, the value of the returned pointer is equal to the value of the specified handle.
If the specified memory block has been discarded or if the memory block has a zero-byte size, this function returns NULL.
Discarded objects always have a lock count of zero.
Semigod 2002-09-27
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主要是用于锁住全局内存，然后对其进行修改，以免在修改过程中，内存块被系统交换或移动。你写过clipboard的代码的话你就明白了
sans 2002-09-27
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锁定内存，防止被移动，特别防止被放入交换文件。
wooingcn 2002-09-27
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因为windows的很多内存块都是可移动的，如果你不锁定它，有可能被系统整理内存时移到别处去。
zhakewei 2002-09-27
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保护机制，线程安全
dockbar 2002-09-27
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保护全局变量，防止多线程重入问题。
