.TH splice 2 2006-04-28 "Linux 2.6.17" "Linux Programmer's Manual"
.SH NAME
splice \- splice data to/from a pipe.
.SH SYNOPSIS
.B #include <sys/splice.h>

.B long splice(int fd_in, loff_t *off_in, int fd_out, loff_t *off_out, size_t bytes, unsigned int flags);

.SH DESCRIPTION
The act of splicing can be seen as a way to connect two ends of a rope
through a kernel buffer, where that buffer is implemented as a pipe. It
provides a means to move data around without copying it to/from kernel/user
address space.

The
.BR splice ()
function splices
.I bytes
of  data between file descriptor
.I fd_in
and
.IR fd_out ,
where one of the descriptors must refer to a pipe. The
.I flags
argument is a series of modifier flags:

.TP 1.9i
.B SPLICE_F_MOVE
Attempt to move pages instead of copying.
.TP
.B SPLICE_F_NONBLOCK
Do not block on io.
.TP
.B SPLICE_F_MORE
More data will be coming in a subsequent splice. This is a helpful hint when
the output descriptor refers to a socket, see also
.B MSG_MORE
(see 
.BR send (2)
and
.B TCP_CORK
.BR tcp (7))
.TP
.B SPLICE_F_GIFT
See
.BR vmsplice (2).

.SH RETURN VALUE
Upon successful completion,
.BR splice ()
shall return the number of bytes
spliced to or from the pipe. Otherwise, it shall return a value of -1 and
.I errno
shall be set to indicate an error.

.SH ERRORS
.TP 1.1i
.B EBADF
.I fd
either not valid, or none of the descriptors refer to a pipe.
.TP
.B EINVAL
Target file system doesn't support splicing, none of the descriptors refer
to a pipe or offset given for non-seekable device.

.SH SEE ALSO
.BR splice (2),
.BR tee (2)

.SH AUTHORS
Jens Axboe <axboe@suse.de>