UDT Reference: UDT Functions

getsockopt

setsockopt

The getsockopt and setsockopt methods read and set up UDT options, respectively.

int getsockopt(

UDTSOCKET u,

int level,

SOCKOPT optname,

char *optval,

int *optlen

);

int setsockopt(

UDTSOCKET u,

int level,

SOCKOPT optname,

const char *optval,

int optlen

);

Parameters

u: [in] Descriptor identifying an listening socket.
level: [in] Ignored. For compatibility use only.
optName: [in] The enum name of UDT option. The names and meanings are listed in the table below:


optval: [in (set), out (get)] The pointer to the value of UDT option of optName.
optlen: [in (set), in/out (get)] The length of the optval.

Name	Type	Meaning	Comment
UDT_MSS	int	maximum packet size (bytes)	default value is 1500.
UDT_SNDSYN	bool	Blocking mode of the data sending	true: blocking sending; false: non-blocking sending. Default value is true.
UDT_RCVSYN	bool	Blocking mode of the data receiving	true: blocking receiving; false: non-blocking receiving. Default value is true.
UDT_CC	CCCFactory* CCC**	Congestion control algorithm option	optval is a pointer to a CCC Factory class. (for setsockopt) optval is a pointer of pointer to a CCC class instance. (for getsockopt)
UDT_FC	int	Maximum flow window size	Default value is 25600.
UDT_SNDBUF	int	UDT sending buffer size limit	Default value is 40960000 bytes.
UDT_RCVBUF	int	UDT receiving buffer size limit	Default value is 40960000 bytes.
UDP_SNDBUF	int	UDP sending buffer size	Default value is 65536 bytes.
UDP_RCVBUF	int	UDP receiving buffer size	Default value is 4194304 bytes.
UDT_LINGER	linger	Linger time on close	Default value is 1 second linger time.
UDT_RENDEZVOUS	bool	Use rendezvous connection setup method	Default value is false (no rendezvous setup).
UDT_SNDTIMEO	int	sending timeout value	Default value is -1 (infinite timeout).
UDT_RCVTIMEO	int	receiving timeout value	Default value is -1 (infinite timeout).

Return Values

On success, 0 is returned; Otherwise, UDT::ERROR is returned and the specific error information can be retrieved by getlasterror.

Error Code	Comment
5001	the specific option cannot be set on a bound socket.
5002	the specific option cannot be set on a connected socket.
5003	the option value or option value length is invalid for setsockopt.
5004	u is an invalid UDT socket.

Description

The setsockopt method sets the UDT option optName with the value of optval. The parameter of optlen is checked to verify the goodness of the option value. Not all options can be set at any state of UDT.

UDT_MSS can only be set before bind; UDT_CC and UDT_FC can only be set before the listen or connect call.

The getsockopt method reads the current option value. The value is written into the buffer pointed by optval and the length is returned in optlen.

Examples

To set data sending in non-blocking mode, the codes can be like:

UDTSOCKET u;

...

bool block = false;