__in __pre 是些什么东西

宏定义, 只是用来标识输入和输了参数, 没什么其他的含义

#define __in __pre __valid __pre __deref __readonly
#define __out __ecount(1) __post __valid __refparam

#define __null
#define __notnull
#define __maybenull
#define __readonly
#define __notreadonly
#define __maybereadonly
#define __valid
#define __notvalid
#define __maybevalid
#define __readableTo(extent)
#define __elem_readableTo(size)
#define __byte_readableTo(size)
#define __writableTo(size)
#define __elem_writableTo(size)
#define __byte_writableTo(size)
#define __deref
#define __pre
#define __post
#define __precond(expr)
#define __postcond(expr)
#define __exceptthat
#define __execeptthat
#define __inner_success(expr)
#define __inner_checkReturn
#define __inner_typefix(ctype)
#define __inner_override
#define __inner_callback
#define __inner_blocksOn(resource)
#define __inner_fallthrough_dec

都是空定义