ReadFileEx |
VB聲明 |
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Declare Function ReadFileEx Lib "kernel32" Alias "ReadFileEx" (ByVal hFile As Long, lpBuffer As Any, ByVal nNumberOfBytesToRead As Long, lpOverlapped As OVERLAPPED, ByVal lpCompletionRoutine As Long) As Long |
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說明 |
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與ReadFile相似,只是它只能用于異步讀操作,并包含了一個完整的回調(diào) |
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返回值 |
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Long,非零表示成功,零表示失敗。會設(shè)置GetLastError |
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參數(shù)表 |
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參數(shù) |
類型及說明 |
hFile |
Long,文件的句柄 |
lpBuffer |
Any,指定容納讀入數(shù)據(jù)的一個緩沖區(qū)。除非讀操作執(zhí)行完畢,否則不要訪問這個緩沖區(qū) |
nNumberOfBytesToRead |
Long,要讀入的字節(jié)數(shù) |
lpOverlapped |
OVERLAPPED,定義了一個異步操作的結(jié)構(gòu)。使用這個函數(shù)時,結(jié)構(gòu)中的hEvent字段會被忽略 |
lpCompletionRoutine |
Long,回調(diào)函數(shù)的返回值 |
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