libdill: Structured Concurrency for C

NAME

tcp_connect_mem - creates a connection to remote TCP endpoint

SYNOPSIS

#include <libdill.h>

int tcp_connect_mem(
    const struct ipaddr* addr,
    struct tcp_storage* mem,
    int64_t deadline);

DESCRIPTION

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

This function creates a connection to a remote TCP endpoint.

This function allows to avoid one dynamic memory allocation by storing the object in user-supplied memory. Unless you are hyper-optimizing use tcp_connect instead.

addr: IP address to connect to.

mem: The structure to store the newly created object in. It must not be deallocated before the object is closed.

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.

The socket can be cleanly shut down using tcp_close function.

This function is not available if libdill is compiled with --disable-sockets option.

RETURN VALUE

In case of success the function returns newly created socket handle. In case of error it returns -1 and sets errno to one of the values below.

ERRORS

ECANCELED: Current coroutine was canceled.
ECONNREFUSED: The target address was not listening for connections or refused the connection request.
ECONNRESET: Remote host reset the connection request.
EHOSTUNREACH: The destination host cannot be reached.
EINVAL: Invalid argument.
EMFILE: The maximum number of file descriptors in the process are already open.
ENETDOWN: The local network interface used to reach the destination is down.
ENETUNREACH: No route to the network is present.
ENFILE: The maximum number of file descriptors in the system are already open.
ENOMEM: Not enough memory.
ETIMEDOUT: Deadline was reached.

EXAMPLE

struct ipaddr addr;
ipaddr_remote(&addr, "www.example.org", 80, 0, -1);
int s = tcp_connect(&addr, -1);
bsend(s, "ABC", 3, -1);
char buf[3];
brecv(s, buf, sizeof(buf), -1);
tcp_close(s);