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What does the recv function return?

What does the recv function return?

The recv() function shall return the length of the message written to the buffer pointed to by the buffer argument. For message-based sockets, such as SOCK_DGRAM and SOCK_SEQPACKET, the entire message shall be read in a single operation.

What is the difference between read () and recv ()?

The only difference between recv() and read(2) is the presence of flags. With a zero flags argument, recv() is generally equivalent to read(2) (but see NOTES).

How do you make a non blocking recv?

In fact, if you reach a point where you actually WANT to wait for data on a socket that was previously marked as “non-blocking”, you could simulate a blocking recv() just by calling select() first, followed by recv(). The “non-blocking” mode is set by changing one of the socket’s “flags”.

What is recv ()?

The recv function is used to read incoming data on connection-oriented sockets, or connectionless sockets. When using a connection-oriented protocol, the sockets must be connected before calling recv. When using a connectionless protocol, the sockets must be bound before calling recv.

Can I use recv with UDP?

Similarly, you would normally use recvfrom() to know where the UDP data was received from. However, you can actually use connect() on UDP socket as an option. In that case, you can use send()/recv() on the UDP socket to send data to the address specified with the connect() and to receive data only from the address.

Is Recvfrom blocking?

By default, Recvfrom() is blocking: when a process issues a Recvfrom() that cannot be completed immediately (because there is no packet), the process is put to sleep waiting for a packet to arrive at the socket. Therefore, a call to Recvfrom() will return immediately only if a packet is available on the socket.

Why would RECV fail?

If the socket is connection oriented and the remote side has shut down the connection gracefully, and all data has been received, a recv will complete immediately with zero bytes received. If the connection has been reset, a recv will fail with the error WSAECONNRESET.

Is recv blocking function?

recv(IPC, Buffer, int n) is a blocking call, that is, if data is available it writes it to the buffer and immediately returns true, and if no data is available it waits for at least n seconds to receive any data.