libdill: Structured Concurrency for C

NAME

ws_done - half-closes a WebSocket connection

SYNOPSIS

#include <libdill.h>

int ws_done(
    int s,
    int status,
    const 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 closes the outbound half of a WebSocket connection. This will, in turn, cause the peer to get EPIPE error after it has received all the data.

s: The WebSocket connection handle.

status: Status to send to the peer. If set zero, no status will be sent.

buf: Message to send to the peer. If set to NULL, no message will be sent. Note that WebSocket protocol limits the sizeof the shutdown message to 125 bytes.

len: Size of the message to send to the peer, in bytes.

deadline: A point in time when the operation should time out, in milliseconds. Use the now function to get your current point in time. 0 means immediate timeout, i.e., perform the operation if possible or return 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 --disable-sockets option.

RETURN VALUE

In case of success the function returns 0. In case of error it returns -1 and sets errno to one of the values below.

ERRORS

EBADF: Invalid handle.
ECANCELED: Current coroutine was canceled.
ENOTSUP: The handle does not support this operation.
EPIPE: The connection was already half-closed.
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);