The meaning of two member variables when Windows WSABUF structure is applied in IOCP

The prototype of the WSABUF structure is as follows:

1 struct __wsabuf 2 {3    u_long len; 4     Char FAR *buf; 5 } wsabuf, *lpwsabuf;

The structure is used in IOCP for the second parameter of the function WSARecv () and the WSASend () function, and the third parameter specifies the number of array elements when the parameter is set to an arrays.

The meaning of the structure in two functions is also slightly different, mainly in Wsabuf::len this parameter. When it does the argument of the WSARecv () function, Len is understood as the length of the buffer wsabuf::buf. When you do the WSASend () function parameter, it is interpreted as the total length of the send, starting with Wsabuf::buf.

The meaning of two member variables when Windows WSABUF structure is applied in IOCP