man pages section 3: Networking Library Functions
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connect(3SOCKET)

Name | Synopsis | Description | Return Values | Errors | Attributes | See Also

Name

    connect– initiate a connection on a socket

Synopsis

    cc [ flag ... ] file ... -lsocket  -lnsl  [ library ... ]
    #include <sys/types.h>
    #include <sys/socket.h>
    
    
    
    int connect(int s, const struct sockaddr *name, int namelen);

Description

    The parameter s is a socket. If it is of type SOCK_DGRAM, connect() specifies the peer with which the socket is to be associated. This address is the address to which datagrams are to be sent if a receiver is not explicitly designated. This address is the only address from which datagrams are to be received. If the socket s is of type SOCK_STREAM, connect() attempts to make a connection to another socket. The other socket is specified by name. name is an address in the communication space of the socket. Each communication space interprets the name parameter in its own way. If s is not bound, then s will be bound to an address selected by the underlying transport provider. Generally, stream sockets can successfully connect() only once. Datagram sockets can use connect() multiple times to change their association. Datagram sockets can dissolve the association by connecting to a null address.

Return Values

    If the connection or binding succeeds, 0 is returned. Otherwise, -1 is returned and sets errno to indicate the error.

Errors

    The call fails if:

    EACCES

    Search permission is denied for a component of the path prefix of the pathname in name.

    EADDRINUSE

    The address is already in use.

    EADDRNOTAVAIL

    The specified address is not available on the remote machine.

    EAFNOSUPPORT

    Addresses in the specified address family cannot be used with this socket.

    EALREADY

    The socket is non-blocking, and a previous connection attempt has not yet been completed.

    EBADF

    s is not a valid descriptor.

    ECONNREFUSED

    The attempt to connect was forcefully rejected. The calling program should close(2) the socket descriptor, and issue another socket(3SOCKET) call to obtain a new descriptor before attempting another connect() call.

    EINPROGRESS

    The socket is non-blocking, and the connection cannot be completed immediately. You can use select(3C) to complete the connection by selecting the socket for writing.

    EINTR

    The connection attempt was interrupted before any data arrived by the delivery of a signal. The connection, however, will be established asynchronously.

    EINVAL

    namelen is not the size of a valid address for the specified address family.

    EIO

    An I/O error occurred while reading from or writing to the file system.

    EISCONN

    The socket is already connected.

    ELOOP

    Too many symbolic links were encountered in translating the pathname in name.

    ENETUNREACH

    The network is not reachable from this host.

    EHOSTUNREACH

    The remote host is not reachable from this host.

    ENOENT

    A component of the path prefix of the pathname in name does not exist.

    ENOENT

    The socket referred to by the pathname in name does not exist.

    ENOSR

    There were insufficient STREAMS resources available to complete the operation.

    ENXIO

    The server exited before the connection was complete.

    ETIMEDOUT

    Connection establishment timed out without establishing a connection.

    EWOULDBLOCK

    The socket is marked as non-blocking, and the requested operation would block.

    The following errors are specific to connecting names in the UNIX domain. These errors might not apply in future versions of the UNIX IPC domain.

    ENOTDIR

    A component of the path prefix of the pathname in name is not a directory.

    ENOTSOCK

    s is not a socket.

    ENOTSOCK

    name is not a socket.

    EPROTOTYPE

    The file that is referred to by name is a socket of a type other than type s. For example, s is a SOCK_DGRAM socket, while name refers to a SOCK_STREAM socket.

Attributes

    See attributes(5) for descriptions of the following attributes:

    ATTRIBUTE TYPE 

    ATTRIBUTE VALUE 

    MT-Level 

    Safe 

See Also

SunOS 5.10  Last Revised 08 Mar 2005

Name | Synopsis | Description | Return Values | Errors | Attributes | See Also