c++ - WriteFile lpNumberOfBytesWritten 小于 nNumberOfBytesToWrite

Question

当调用 WriteFile 时，返回的 lpNumberOfBytesWritten 是否可以在未发生错误的同步写入模式下小于 nNumberOfBytesToWrite(返回为 真)？写入到适当的文件(不是套接字、管道或其他特殊句柄)。 lpOverlapped 未使用。

从 docs 中并不完全清楚.

Answer 1

文档指出:

The WriteFile function returns when one of the following conditions occur:

• The number of bytes requested is written.
• A read operation releases buffer space on the read end of the pipe (if the write was blocked). For more information, see the Pipes section.
• An asynchronous handle is being used and the write is occurring asynchronously.
• An error occurs.

只有其中第一个符合您的标准，所以答案是文档很清楚 *lpNumberOfBytesWritten 总是等于 nNumberOfBytesToWrite 当函数在您调用时返回指定。