.\" -*-nroff-*-
.TH fdpass 3 "28 November 2003" "Straylight/Edgeware" "mLib utilities library"
.SH NAME
fdpass \- file descriptor passing
.\" @fdpass_send
.\" @fdpass_recv
.SH SYNOPSIS
.nf
.B "#include <mLib/fdpass.h>"

.BI "ssize_t fdpass_send(int " sock ", int " fd ", const void *" p ", size_t " sz );
.BI "ssize_t fdpass_recv(int " sock ", int *" fd ", void *" p ", size_t " sz );
.fi
.SH DESCRIPTION
The function
.B fdpass_send
sends the file descriptor
.I fd
as ancillary data attached to the buffer pointed to by
.I p
of length
.I sz
over the Unix-domain socket
.IR sock .
It returns the amount of data sent, or \-1 on error.  For more details,
see
.BR sendmsg (2)
and
.BR unix (7).
.PP
The function
.B fdpass_recv
receives at most
.I sz
bytes of data into the buffer pointed to by
.IR p ,
together with at most one file descriptor passed as ancillary data,
which is written to the integer pointed to by
.IR fd .
Other file descriptors received are closed; any other ancillary messages
are ignored.  If no file descriptor is received,
.BI * fd
is set to \-1.  The function returns the number of bytes read, or \-1 on
error.  For more details, see
.BR recvmsg (2)
and
.BR unix (7).
.SH "SEE ALSO"
.BR recvmsg (2),
.BR sendmsg (2),
.BR mLib (3),
.BR unix (7).
.SH AUTHOR
Mark Wooding, <mdw@distorted.org.uk>