+++ /dev/null
-.\" This manpage is Copyright (C) 2006 Jens Axboe
-.\" and Copyright (C) 2006 Michael Kerrisk <mtk.manpages@gmail.com>
-.\"
-.\" %%%LICENSE_START(VERBATIM)
-.\" Permission is granted to make and distribute verbatim copies of this
-.\" manual provided the copyright notice and this permission notice are
-.\" preserved on all copies.
-.\"
-.\" Permission is granted to copy and distribute modified versions of this
-.\" manual under the conditions for verbatim copying, provided that the
-.\" entire resulting derived work is distributed under the terms of a
-.\" permission notice identical to this one.
-.\"
-.\" Since the Linux kernel and libraries are constantly changing, this
-.\" manual page may be incorrect or out-of-date. The author(s) assume no
-.\" responsibility for errors or omissions, or for damages resulting from
-.\" the use of the information contained herein. The author(s) may not
-.\" have taken the same level of care in the production of this manual,
-.\" which is licensed free of charge, as they might when working
-.\" professionally.
-.\"
-.\" Formatted or processed versions of this manual, if unaccompanied by
-.\" the source, must acknowledge the copyright and authors of this work.
-.\" %%%LICENSE_END
-.\"
-.TH VMSPLICE 2 2014-10-02 "Linux" "Linux Programmer's Manual"
-.SH NAME
-vmsplice \- splice user pages into a pipe
-.SH SYNOPSIS
-.nf
-.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
-.B #include <fcntl.h>
-.B #include <sys/uio.h>
-
-.BI "ssize_t vmsplice(int " fd ", const struct iovec *" iov ,
-.BI " unsigned long " nr_segs ", unsigned int " flags );
-.fi
-.\" Return type was long before glibc 2.7
-.SH DESCRIPTION
-.\" Linus: vmsplice() system call to basically do a "write to
-.\" the buffer", but using the reference counting and VM traversal
-.\" to actually fill the buffer. This means that the user needs to
-.\" be careful not to reuse the user-space buffer it spliced into
-.\" the kernel-space one (contrast this to "write()", which copies
-.\" the actual data, and you can thus reuse the buffer immediately
-.\" after a successful write), but that is often easy to do.
-The
-.BR vmsplice ()
-system call maps
-.I nr_segs
-ranges of user memory described by
-.I iov
-into a pipe.
-The file descriptor
-.I fd
-must refer to a pipe.
-
-The pointer
-.I iov
-points to an array of
-.I iovec
-structures as defined in
-.IR <sys/uio.h> :
-
-.in +4n
-.nf
-struct iovec {
- void *iov_base; /* Starting address */
- size_t iov_len; /* Number of bytes */
-};
-.in
-.fi
-
-The
-.I flags
-argument is a bit mask that is composed by ORing together
-zero or more of the following values:
-.TP 1.9i
-.B SPLICE_F_MOVE
-Unused for
-.BR vmsplice ();
-see
-.BR splice (2).
-.TP
-.B SPLICE_F_NONBLOCK
-.\" Not used for vmsplice
-.\" May be in the future -- therefore EAGAIN
-Do not block on I/O; see
-.BR splice (2)
-for further details.
-.TP
-.B SPLICE_F_MORE
-Currently has no effect for
-.BR vmsplice (),
-but may be implemented in the future; see
-.BR splice (2).
-.TP
-.B SPLICE_F_GIFT
-The user pages are a gift to the kernel.
-The application may not modify this memory ever,
-.\" FIXME . Explain the following line in a little more detail:
-or page cache and on-disk data may differ.
-Gifting pages to the kernel means that a subsequent
-.BR splice (2)
-.B SPLICE_F_MOVE
-can successfully move the pages;
-if this flag is not specified, then a subsequent
-.BR splice (2)
-.B SPLICE_F_MOVE
-must copy the pages.
-Data must also be properly page aligned, both in memory and length.
-.\" FIXME
-.\" It looks like the page-alignment requirement went away with
-.\" commit bd1a68b59c8e3bce45fb76632c64e1e063c3962d
-.\"
-.\" .... if we expect to later SPLICE_F_MOVE to the cache.
-.SH RETURN VALUE
-Upon successful completion,
-.BR vmsplice ()
-returns the number of bytes transferred to the pipe.
-On error,
-.BR vmsplice ()
-returns \-1 and
-.I errno
-is set to indicate the error.
-.SH ERRORS
-.TP
-.B EAGAIN
-.B SPLICE_F_NONBLOCK
-was specified in
-.IR flags ,
-and the operation would block.
-.TP
-.B EBADF
-.I fd
-either not valid, or doesn't refer to a pipe.
-.TP
-.B EINVAL
-.I nr_segs
-is greater than
-.BR IOV_MAX ;
-or memory not aligned if
-.B SPLICE_F_GIFT
-set.
-.TP
-.B ENOMEM
-Out of memory.
-.SH VERSIONS
-The
-.BR vmsplice ()
-system call first appeared in Linux 2.6.17;
-library support was added to glibc in version 2.5.
-.SH CONFORMING TO
-This system call is Linux-specific.
-.SH NOTES
-.BR vmsplice ()
-follows the other vectorized read/write type functions when it comes to
-limitations on number of segments being passed in.
-This limit is
-.B IOV_MAX
-as defined in
-.IR <limits.h> .
-At the time of this writing, that limit is 1024.
-.SH SEE ALSO
-.BR splice (2),
-.BR tee (2)
-.SH COLOPHON
-This page is part of release 3.79 of the Linux
-.I man-pages
-project.
-A description of the project,
-information about reporting bugs,
-and the latest version of this page,
-can be found at
-\%http://www.kernel.org/doc/man\-pages/.
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