6.2.3.10 recv/recvfrom

The recv and recvfrom functions are used to read data from TCP and UDP sockets, respectively, and their operation is otherwise identical.

The host MCU application calls the recv or recvfrom function with a pre allocated buffer. When the SOCKET_MSG_RECV or SOCKET_MSG_RECVFROM event callback arrives, this buffer must have the received data.

The received data size indicates the status as follows:

• Positive – data is received
• Zero – socket connection is terminated
• Negative – indicates an error

In the case of TCP sockets, it is recommended to call the recv function after each successful socket connection (client or server). Otherwise, the received data is buffered in the ATWINC15x0 firmware wasting the system's resources until the socket is explicitly closed using a close function call.