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.
void FreeRTOS_FD_SET( Socket_t xSocket, SocketSet_t xSocketSet, BaseType_t xSelectBits );
Add a socket to a socket set, and set the event bits of interest for the
added socket. A socket can only be a member of one set at any time.
ipconfigSUPPORT_SELECT_FUNCTION must be set to 1 in
for FreeRTOS_FD_SET() to be available.
Socket Sets allow an application RTOS task to block on multiple sockets
To use a socket set:
Create a socket set by calling FreeRTOS_CreateSocketSet().
A socket set is equivalent to the Berkeley sockets fd_set type.
Add one or more sockets to the set using calls to FreeRTOS_FD_SET().
FreeRTOS_FD_SET() is equivalent to the Berkeley sockets FD_SET() macro.
Call FreeRTOS_Select() to test the
sockets in the set to see if any of the sockets have an event
If FreeRTOS_select() returns a non-zero value then check all
sockets in the set using a call to FreeRTOS_FD_ISSET()
to determine which events are pending.
The event bits of interest are set using the xSelectBits parameter,
which can take a bitwise OR combination of one or more of the following
For a socket that is reading data, the eSELECT_READ event
will be pending in a socket as long as the socket contains
For a socket that is listening for new connections, the
eSELECT_READ event will be pended each time a new connection
The eSELECT_WRITE event will remain pending as long as the
socket has space for writing.
If a TCP socket is actively connecting to a pear the
eSELECT_WRITE event will be triggered as soon as the connection
One the eSELECT_WRITE event has been pended it should either
be disabled, or the caller should write enough data to the
socket so as to completely fill up the transmit buffer -
otherwise the pending eSELECT_WRITE event will not be cleared.
The eSELECT_EXCEPT event will become pending if the socket
The FreeRTOS_FD_CLR() API function is used to
clear event bits or remove a socket from a socket set.
The socket being added to the set.
The socket set to which the socket is being added.
The events that will cause the socket to unblock a call
to FreeRTOS_select(). See the table above for valid
See the example on the FreeRTOS_select()