libdill: Structured Concurrency for C


tcp_close - closes TCP connection in an orderly manner


#include <libdill.h>

int tcp_close(
    int s,
    int64_t deadline);


TCP protocol is a reliable bytestream protocol for transporting data over network. It is defined in RFC 793.

This function closes a TCP socket cleanly. Unlike hclose it lets the peer know that it is shutting down and waits till the peer acknowledged the shutdown. If this terminal handshake cannot be done it returns error. The socket is closed even in the case of error.

It can also be used to close TCP listener socket in which case it's equivalent to calling hclose.

s: The TCP socket.

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.


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



struct ipaddr addr;
ipaddr_local(&addr, NULL, 5555, 0);
int ls = tcp_listen(&addr, 10);
int s = tcp_accept(ls, NULL, -1);
bsend(s, "ABC", 3, -1);
char buf[3];
brecv(s, buf, sizeof(buf), -1);


brecv(3) brecvl(3) bsend(3) bsendl(3) now(3) tcp_accept(3) tcp_accept_mem(3) tcp_connect(3) tcp_connect_mem(3) tcp_done(3) tcp_fromfd(3) tcp_fromfd_mem(3) tcp_listen(3) tcp_listen_mem(3) tcp_listener_fromfd(3) tcp_listener_fromfd_mem(3)