winsock.h accept函数

2191265529

1. WINSOCK_API_LINKAGE SOCKET WSAAPI accept(
   
2.   SOCKET   s,
   
3.   sockaddr *addr,
   
4.   int      *addrlen
   
5. );

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Parameters
s

A descriptor that identifies a socket that has been placed in a listening state with the listen function. The connection is actually made with the socket that is returned by accept.

addr

An optional pointer to a buffer that receives the address of the connecting entity, as known to the communications layer. The exact format of the addr parameter is determined by the address family that was established when the socket from the sockaddr structure was created.

addrlen

An optional pointer to an integer that contains the length of structure pointed to by the addr parameter.

第二个参数会返回一些客户端的IP,端口，协议族等信息，第三个参数干嘛用的？

Syc

2191265529 发表于 2018-7-27 14:08
sinaddr 是个结构体，不管结构体里面放了什么样的数据或者说更改了什么样的数据，它的length应该不会改变 ...

总长度不变，但是里面有的有效长度是多少就不一定了。
而且第二个参数现在你是传的结构体，实际上也可以直接传递个char类型的数组，东西一样会放进去

Syc

第三个参数就是第二个参数的结构的大小

2191265529

Syc 发表于 2018-7-26 17:26
第三个参数就是第二个参数的结构的大小

那它干嘛要定义成int *类型的，而bind直接int类型。不用返回什么信息的吗？

Syc

The addrlen argument is a value-result argument: the caller must initialize it to contain the size (in bytes) of the structure pointed to by addr; on return it will contain the actual size of the peer address.

addrlen在调用函数时被设置为addr指向区域的长度，在函数调用结束后被设置为实际地址信息的长度。

他不仅仅是作为一个传入值，函数返回的时候同时又是作为一个传出值！所以要用指针

2191265529

Syc 发表于 2018-7-26 18:15
The addrlen argument is a value-result argument: the caller must initialize it to contain the size ( ...

sinaddr 是个结构体，不管结构体里面放了什么样的数据或者说更改了什么样的数据，它的length应该不会改变吧？