Some Windows structures end with an array of size 1. If you try to access any members of that array beyond the first, you may get a static analysis error.
typedef struct THINGGROUP { DWORD NumberOfThings; THING Things[ANYSIZE_ARRAY]; }; void ProcessAllTheThings(_In_ const THINGGROUP* group) { for (DWORD index = 0; index < group->NumberOfThings; index++) { // static analysis warning: possible index past end of array // when NumberOfThings >= 2 ProcessOneThing(group->Things[index]); } }
How do you tell the Visual Studio static analysis tool that the size of the Things
array is specified by the NumberOfThings
member?
You use the _Field_size_
annotation. The documentation doesn’t really give an example of this case, so here you go:
typedef struct THINGGROUP { DWORD NumberOfThings; _Field_size_(NumberOfThings) THING Things[ANYSIZE_ARRAY]; };
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