FreeRTOS+TCP is still in the lab
FreeRTOS+TCP is already used in
commercial products and we encourage
you to try it yourself.
Be aware however that we are
still refining its design, and the
source code and documentation do not
yet meet Real Time Engineers Ltd's strict quality standards.
Please use the forum for support,
feedback and ideas,
or contact us directly if you have a specific business interest.
Socket_t FreeRTOS_accept( Socket_t xServerSocket,
struct freertos_sockaddr *pxAddress,
socklen_t *pxAddressLength );
Accept a connection on a TCP socket.
The socket must first have been successfully created by a call to
bound to a port using a call to
and placed into the Listening state using a call to
By default a new socket (a child socket) will be created to handle any accepted connections.
The new socket will be returned by
and can be used immediately. The child socket inherits all the properties
from the parent socket.
Optionally the FREERTOS_SO_REUSE_LISTEN_SOCKET parameter can be used
with a call to FreeRTOS_setsockopt()
to configure the parent socket to
handle any accepted connections itself - without creating a child socket
for this purpose. This is a useful way to save resources when the socket will
only handle a single connection at a time. For example, if the socket
is used to implement a telnet server that only permits one simultaneous
FreeRTOS_accept() has an optional timeout. The timeout defaults to
ipconfigSOCK_DEFAULT_RECEIVE_BLOCK_TIME, and is modified using the
FREERTOS_SO_RCVTIMEO parameter in a call to FreeRTOS_setsockopt(). If
the accept operation does not succeed immediately then the calling RTOS task
will be held in the Blocked state (so that other RTOS tasks can execute) until
either a connection is accepted, or the timeout expires.
The handle of the listening socket on which new connections
are to be accepted.
A pointer to a freertos_sockaddr structure that will be
filled (by FreeRTOS_accept()) with the IP address and
port number of the socket from which a connection was
Not currently used, but should be set to
sizeof( struct freertos_sockaddr ) to ensure future
If a connection from a remote socket is accepted and a new local socket
is created to handle the accepted connection then a handle to the new
socket is returned.
If xServerSocket is not a valid TCP socket then then FREERTOS_INVALID_SOCKET
If xServerSocket is not in the Listening state (see
then FREERTOS_INVALID_SOCKET is returned.
If a timeout occurs before a connection from a remote socket is accepted
then NULL is returned.
Note that, because FreeRTOS does not implement errno, the
behaviour in the presence of an error is necessarily different to that of
connect() functions that are fully compliant with the expected Berkeley
See the "Creating, configuring and binding a TCP server socket" source
code example in the
"Creating Configuring and Binding TCP Client and Server Sockets"
section of the FreeRTOS+TCP networking tutorial.