@CHIP-RTOS C Library - TCP/IP API

sendto

Transmit a datagram.

int sendto ( int sd, const char far *bufptr, int bufLen,
             int flags, const struct sockaddr far *toPtr,
             int *error );

Parameters

sd

Socket descriptor.

bufptr

Pointer to output buffer containing characters to be transmitted.

bufLen

Maximum characters to output from bufptr .

flags

Wait option:

• MSG_BLOCKING - Wait for data send to complete.
  
• MSG_DONTWAIT - Don't wait for data send to complete.
  

toPtr

Data destination, pointer to a sockaddr_in (IPv4) or sockaddr_in6 (IPv6, SC1x3/SC2x only! ) data structure.

error

Output parameter:  Failure code, 0 on success.

Return Value

-1: Failure, see error value reported
otherwise: Count of bytes transfered into the socket send queue.

Comments

This API function applies only to UDP sockets.   This function will output up to bufLen bytes from the buffer at bufptr to the IP address specified by the sockaddr_in (IPv4) structure or the sockaddr_in6 (IPv6, SC1x3/SC2x only! ) structure referenced by the toPtr parameter.

This function's prototype takes a pointer to the generic type sockaddr for its toPtr parameter, for compatibility between IPv4 and IPv6 protocols.   The pointer to the sockaddr_in (IPv4) or sockaddr_in6 (IPv6, SC1x3/SC2x only! ) data structure which is actually used should be cast to a sockaddr type pointer to avoid compiler warnings, "Suspicious pointer conversion".

The MSG_BLOCKING mode will not work if the socket has been put into non-blocking mode using the Set_Blocking_Mode API.

SC1x3/SC2x Comments

The actual library function reached here is named sendto_ipstackV2 (when neither of the compilation switches discussed below are used).   The name change occurs due to a macro in the library header file.

This legacy version of sendto() specified here is not compatible to the BSD 4.4 Socket API.   The sendto() function can be used in BSD 4.4 compatible mode if the compilation switch

     #define BSD44_SOCKET_API_STYLE

is defined in the user application prior to including the Beck C-Library header files.   Using this switch the C-Library TCPIP_Socket.H include file redefines sendto() to sendto_bsd().  The parameters to sendto_bsd() are identical to the parameters of the BSD4.4 socket sendto() function.

The sendto_bsd() method uses dynamical linking, so therefore executes faster than this legacy API's sofware interrupt method. The compilation switch

     #define TCPIP_DYN_LINK_SOCK

may be defined in the user application prior to including the Beck C-Library header files to implement this legacy sendto() method using the faster sendto_bsd() dynamic linked API.

The first compilation switch takes precedence.   This second compilation option, TCPIP_DYN_LINK_SOCK will be not affect this API when the first option (BSD44_SOCKET_API_STYLE ) is defined.

See Also

recvfrom        opensocket        Set_Blocking_Mode
sendto_bsd        send        sendto_bsd

RTOS API

This library function invokes a RTOS software interrupt. Refer to this RTOS API function's documentation for more details.

Supported since or modified in @CHIP-RTOS version

SC12	SC13	SC11	SC1x3	SC2x
V1.00	V1.00	V1.00	V0.90	V1.00