c - What is the size of HANDLE? -

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for exercise, @ startupinfo structure. can see last 3 elements has type handle.

so want know size handle has. know size of handle?

the windows handle type isn't opaque type. windows defines couple of properties can depend on. main 1 answer your question: of type void *. windows data types entry on msdn:

handle

a handle object.

this type declared in winnt.h follows:

typedef pvoid handle;

later on in table can see pvoid defined void *.

so handle has same size void *. or in other words, it's 32 bits when using 32-bit compiler , 64 bits when using 64-bit compiler. shouldn't need hard code either of these values in code, instead use sizeof(handle).

the other property of windows handle type obscure, , barely documented: kernel handles the bottom 2 bits zero. shouldn't need depend on in code, , can see never want to. mention completeness , emphasize how microsoft has defined handle more internal implementation detail.


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