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.
BaseType_t FreeRTOS_FD_ISSET( Socket_t xSocket, SocketSet_t xSocketSet );
Check if a socket in a socket set has an event bit set.
ipconfigSUPPORT_SELECT_FUNCTION must be set to 1 in
for FreeRTOS_FD_ISSET() 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 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 functions clears
event bits of interest and removes a socket from a set.
The socket within the socket set being tested to see if
it has any event bits set.
The socket set to which the socket is being added.
The function returns a bit-mask of the values eSELECT_READ (1),
eSELECT_WRITE (2) and eSELECT_EXCEPT (4). Only the bits of interest
specified using calls to FreeRTOS_FD_SET()
will be returned.
See the example on the FreeRTOS_select()