小记setsockopt

以下内容摘自于<msdn>

The setsockopt function sets a socket option.

int setsockopt(  SOCKET s,  int level,  int optname,  const char* optval,  int optlen);

 

Remarks

The setsockopt function sets the current value for a socket option associated with a socket of any type, in any state. Although options can exist at multiple protocol levels, they are always present at the uppermost socket level. Options affect socket operations, such as whether expedited data (OOB data for example) is received in the normal data stream, and whether broadcast messages can be sent on the socket.

Note  If the setsockopt function is called before the bind function, TCP/IP options will not be checked with TCP/IP until the bind occurs. In this case, the setsockopt function call will always succeed, but the bind function call may fail because of an early setsockopt failing.

Note  If a socket is opened, a setsockopt call is made, and then a sendto call is made, Windows Sockets performs an implicit bind function call.

 

level = SOL_SOCKET

Value Type Meaning SO_BROADCAST BOOL Enables transmission and receipt of broadcast messages on the socket. SO_CONDITIONAL_ACCEPT BOOL Enables sockets to delay the acknowledgment of a connection until after the WSAAccept condition function is called. SO_DEBUG BOOL Records debugging information. SO_DONTLINGER BOOL Does not block close waiting for unsent data to be sent. Setting this option is equivalent to setting SO_LINGER with l_onoff set to zero. SO_DONTROUTE BOOL Does not route: sends directly to interface. Succeeds but is ignored on AF_INET sockets; fails on AF_INET6 sockets with WSAENOPROTOOPT. Not supported on ATM sockets (results in an error). SO_GROUP_PRIORITY int Reserved. SO_KEEPALIVE BOOL Sends keep-alives. Not supported on ATM sockets (results in an error). SO_LINGER LINGER Lingers on close if unsent data is present. SO_OOBINLINE BOOL Receives OOB data in the normal data stream. (See section Protocol Independent Out-Of-band Data for a discussion of this topic.) SO_RCVBUF int Specifies the total per-socket buffer space reserved for receives. This is unrelated to SO_MAX_MSG_SIZE or the size of a TCP window. SO_REUSEADDR BOOL Allows the socket to be bound to an address that is already in use. (See bind.) Not applicable on ATM sockets. SO_EXCLUSIVEADDRUSE BOOL Enables a socket to be bound for exclusive access. Does not require administrative privilege. SO_SNDBUF int Specifies the total per-socket buffer space reserved for sends. This is unrelated to SO_MAX_MSG_SIZE or the size of a TCP window. PVD_CONFIG Service Provider Dependent This object stores the configuration information for the service provider associated with socket s. The exact format of this data structure is service provider specific.

level = IPPROTO_TCP1

Value Type Meaning TCP_NODELAY BOOL Disables the Nagle algorithm for send coalescing. 1     included for backward compatibility with Windows Sockets 1.1

level = NSPROTO_IPX

Note  Windows NT supports all IPX options. Windows Me/98/95 support only the following options:

Note  IPX_PTYPE
IPX_FILTERPTYPE
IPX_DSTYPE
IPX_RECVHDR
IPX_MAXSIZE (used with the getsockopt function)
IPX_ADDRESS (used with the getsockopt function)

Value Type Meaning IPX_PTYPE int Sets the IPX packet type. IPX_FILTERPTYPE int Sets the receive filter packet type IPX_STOPFILTERPTYPE int Stops filtering the filter type set with IPX_FILTERTYPE IPX_DSTYPE int Sets the value of the data stream field in the SPX header on every packet sent. IPX_EXTENDED_ADDRESS BOOL Sets whether extended addressing is enabled. IPX_RECVHDR BOOL Sets whether the protocol header is sent up on all receive headers. IPX_RECEIVE_BROADCAST BOOL Indicates broadcast packets are likely on the socket. Set to TRUE by default. Applications that do not use broadcasts should set this to FALSE for better system performance. IPX_IMMEDIATESPXACK BOOL Directs SPX connections not to delay before sending an ACK. Applications without back-and-forth traffic should set this to TRUE to increase performance.

BSD options not supported for setsockopt are shown in the following table.

Value Type Meaning SO_ACCEPTCONN BOOL Socket is listening. SO_RCVLOWAT int Receives low watermark. SO_RCVTIMEO int Receives time-out in milliseconds (available in the Microsoft implementation of Windows Sockets 2). SO_SNDLOWAT int Sends low watermark. SO_SNDTIMEO int Sends time-out in milliseconds (available in the Microsoft implementation of Windows Sockets 2). SO_TYPE int Type of the socket.