connect.man

来自「eCos操作系统源码」· MAN 代码 · 共 76 行

NAME
       connect - initiate a connection on a socket

SYNOPSIS
       #include <network.h>

       int  connect(int  sockfd,  struct sockaddr *serv_addr, int
       addrlen);

DESCRIPTION
       The parameter sockfd is a socket.  If  the  socket  is  of
       type  SOCK_DGRAM,  this call specifies the peer with which
       the socket is to be associated; this address  is  that  to
       which  datagrams are to be sent, and the only address from
       which datagrams are to be received.  If the socket  is  of
       type  SOCK_STREAM, this call attempts to make a connection
       to another socket.   The  other  socket  is  specified  by
       serv_addr, which is an address in the communications space
       of the socket.  Each communications space  interprets  the
       serv_addr  parameter  in  its  own way.  Generally, stream
       sockets may successfully connect only once; datagram sock-
       ets may use connect multiple times to change their associ-
       ation.  Datagram sockets may dissolve the  association  by
       connecting  to an address with the sa_family sockaddr mem-
       ber set to AF_UNSPEC.

RETURN VALUE
       If the connection or binding succeeds, zero  is  returned.
       On  error, -1 is returned, and errno is set appropriately.

ERRORS
       The following are general socket errors only.   There  may
       be other domain-specific error codes.

       EBADF   Bad descriptor.

       ENOTSOCK
               The descriptor is not associated with a socket.

       EISCONN The socket is already connected.

       ECONNREFUSED
               Connection refused at server.

       ETIMEDOUT
               Timeout while attempting connection.

       ENETUNREACH
               Network is unreachable.

       EADDRINUSE
               Address is already in use.

       EINPROGRESS
               The socket is non-blocking and the connection can-
               not  be  completed immediately.  It is possible to
               select(2) or poll(2) for completion  by  selecting
               the  socket  for  writing.  After select indicates
               writability,  use  getsockopt(2)   to   read   the
               SO_ERROR  option  at level SOL_SOCKET to determine
               whether connect completed  successfully  (SO_ERROR
               is zero) or unsuccessfully (SO_ERROR is one of the
               usual error codes  listed  above,  explaining  the
               reason for the failure).

       EALREADY
               The  socket is non-blocking and a previous connec-
               tion attempt has not yet been completed.

       EAFNOSUPPORT
               The passed address didn't have the correct address
               family in its sa_family field.

       EACCES  The  user  tried to connect to a broadcast address
               without having the socket broadcast flag  enabled.