Metrologic Optimus R, Руководство по программированию

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Chapter 3 Terminal Specific Function Library 159
Syntax int sendto (SOCKET s, char *buf, int len, int flags, struct sockaddr *to, int
tolen);
s Descriptor identifying a connected socket
buf Pointer to the buffer in which data is to be sent
len Maximum number of bytes to be sent
flags MSG_OOB: process out-of-band data
MSG_DONTROUTE: bypass routing, use direct interface
to Pointer to a sockaddr structure containing the address of the
target socket
tolen Length of address indicated by
to
Example (?)
Description This routine writes outgoing data to a specified send buffer ( buf ) on a socket.
The address of the targe is given by to with tolen specifying its size. The length
of the message is given by
len
. It is typically used on a connectionless socket.
The application can avoid this blocking behavior by using socket_cansend() to
make sure there is data available before calling sendto(). (?)
The whole data may not be sent at one time. Check the return value in case the
send buffer overflows. (?)
Return If successful, it returns a non-negative integer (>=0) indicating the number of
bytes sent.
On error, it returns -1.
The global variable
errno
is set to indicate the error condition encountered.
See Also recvfrom, sendto, socket_cansend
setsockopt
Purpose To set options on a socket.
Syntax int setsockopt (SOCKET s, int level, int optname, char *optval, int optlen);
s Descriptor identifying a socket.
level Level at which the option resides:
SOL_SOCKET, IPPROTO_TCP, or IPPROTO_IP
optname Socket option for which the value is to be set.
optval Pointer to the buffer in which the value for the requested
option is specified.
optlen Length of the buffer indicated by
optval
Example (?)
Description This routine sets the current value for a socket option associated with a socket
of any type, in any state.