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.\" This documentation was written by Pawel Jakub Dawidek under sponsorship from
.\" the FreeBSD Foundation.
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.\" $FreeBSD: head/lib/libc/sys/connectat.2 267774 2014-06-23 08:25:03Z bapt $
.\"
.Dd February 13, 2013
.Dt CONNECTAT 2
.Os
.Sh NAME
.Nm connectat
.Nd initiate a connection on a socket
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/types.h
.In sys/socket.h
.Pp
.In fcntl.h
.Ft int
.Fn connectat "int fd" "int s" "const struct sockaddr *name" "socklen_t namelen"
.Sh DESCRIPTION
The
.Fn connectat
system call initiates a connection on a socket.
It works just like the
.Xr connect 2
system call with two exceptions:
.Pp
.Bl -enum -offset indent -compact
.It
It is limited to sockets in the PF_LOCAL domain.
.Pp
.It
If the file path stored in the
.Fa sun_path
field of the sockaddr_un structure is a relative path, it is located relative
to the directory associated with the file descriptor
.Fa fd .
If
.Fn connectat
is passed the special value
.Dv AT_FDCWD
in the
.Fa fd
parameter, the current working directory is used and the behavior is identical
to a call to
.Xr connect 2 .
.El
.Sh RETURN VALUES
.Rv -std connectat
.Sh ERRORS
The
.Fn connectat
system call may fail with the same errors as the
.Xr connect 2
system call for a UNIX domain socket or with the following errors:
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa sun_path
field does not specify an absolute path and the
.Fa fd
argument is neither
.Dv AT_FDCWD
nor a valid file descriptor.
.It Bq Er ENOTDIR
The
.Fa sun_path
field is not an absolute path and
.Fa fd
is neither
.Dv AT_FDCWD
nor a file descriptor associated with a directory.
.El
.Sh SEE ALSO
.Xr bindat 2 ,
.Xr connect 2 ,
.Xr socket 2 ,
.Xr unix 4
.Sh AUTHORS
The
.Nm
was developed by
.An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net
under sponsorship from the FreeBSD Foundation.