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WS_RECV(3) libdill Library Functions WS_RECV(3) NAME ws_recv - receives a WebSocket message SYNOPSIS #include <libdill.h> ssize_t ws_recv( int s, int* flags, void* buf, size_t len, int64_t deadline); DESCRIPTION WARNING: This is experimental functionality and the API may change in the future. WebSocket is a message-based protocol defined in RFC 6455. It can be used as a bidirectional communication channel for communication with a web server. This function receives one WebSocket message. It is very much the same as mrecv except that it returns the type of the message (either text or binary). s: The socket handle. flags: Out parameter. Possible values are either WS_BINARYor WS_TEXT. buf: Buffer to receive the data to. len: Size of the buffer, in bytes. deadline: A point in time when the operation should time out, in mil- liseconds. Use the now function to get your current point in time. 0 means immediate timeout, i.e., perform the operation if possible or re- turn without blocking if not. -1 means no deadline, i.e., the call will block forever if the operation cannot be performed. This function is not available if libdill is compiled with --dis- able-sockets option. RETURN VALUE In case of success the function returns size of the received message, in bytes. In case of error it returns -1 and sets errno to one of the values below. ERRORS • EBADF: Invalid handle. • EBUSY: The handle is currently being used by a different coroutine. • ECANCELED: Current coroutine was canceled. • ECONNRESET: Broken connection. • EINVAL: Invalid argument. • EMSGSIZE: The data won't fit into the supplied buffer. • ENOTSUP: The handle does not support this operation. • ETIMEDOUT: Deadline was reached. EXAMPLE struct ipaddr addr; ipaddr_remote(&addr, "www.example.org", 80, 0, -1); int s = tcp_connect(&addr, -1); s = ws_attach_client(s, "/", "www.example.org", WS_TEXT, -1); ws_send(s, WS_TEXT, "Hello, world!", 13, -1); int flags; char buf[256]; ssize_t sz = ws_recv(s, &flags, buf, sizeof(buf), -1); assert(flags & WS_TEXT); s = ws_detach(s, -1); tcp_close(s, -1); SEE ALSO mrecv(3) mrecvl(3) msend(3) msendl(3) now(3) ws_attach_client(3) ws_at- tach_client_mem(3) ws_attach_server(3) ws_attach_server_mem(3) ws_de- tach(3) ws_done(3) ws_recvl(3) ws_request_key(3) ws_response_key(3) ws_send(3) ws_sendl(3) ws_status(3) libdill WS_RECV(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLE | SEE ALSO
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