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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:22 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:22 +0000 |
commit | 3d08cd331c1adcf0d917392f7e527b3f00511748 (patch) | |
tree | 312f0d1e1632f48862f044b8bb87e602dcffb5f9 /man2/vmsplice.2 | |
parent | Adding debian version 6.7-2. (diff) | |
download | manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.tar.xz manpages-3d08cd331c1adcf0d917392f7e527b3f00511748.zip |
Merging upstream version 6.8.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man2/vmsplice.2')
-rw-r--r-- | man2/vmsplice.2 | 162 |
1 files changed, 0 insertions, 162 deletions
diff --git a/man2/vmsplice.2 b/man2/vmsplice.2 deleted file mode 100644 index ccbf2c6..0000000 --- a/man2/vmsplice.2 +++ /dev/null @@ -1,162 +0,0 @@ -.\" This manpage is Copyright (C) 2006 Jens Axboe -.\" and Copyright (C) 2006 Michael Kerrisk <mtk.manpages@gmail.com> -.\" -.\" SPDX-License-Identifier: Linux-man-pages-copyleft -.\" -.TH vmsplice 2 2023-10-31 "Linux man-pages 6.7" -.SH NAME -vmsplice \- splice user pages to/from a pipe -.SH LIBRARY -Standard C library -.RI ( libc ", " \-lc ) -.SH SYNOPSIS -.nf -.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */" -.B #include <fcntl.h> -.P -.BI "ssize_t vmsplice(int " fd ", const struct iovec *" iov , -.BI " size_t " 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. -If -.I fd -is opened for writing, the -.BR vmsplice () -system call maps -.I nr_segs -ranges of user memory described by -.I iov -into a pipe. -If -.I fd -is opened for reading, -.\" Since Linux 2.6.23 -.\" commit 6a14b90bb6bc7cd83e2a444bf457a2ea645cbfe7 -the -.BR vmsplice () -system call fills -.I nr_segs -ranges of user memory described by -.I iov -from a pipe. -The file descriptor -.I fd -must refer to a pipe. -.P -The pointer -.I iov -points to an array of -.I iovec -structures as described in -.BR iovec (3type). -.P -The -.I flags -argument is a bit mask that is composed by ORing together -zero or more of the following values: -.TP -.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: -otherwise the 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 STANDARDS -Linux. -.SH HISTORY -Linux 2.6.17, -glibc 2.5. -.SH NOTES -.BR vmsplice () -follows the other vectorized read/write type functions when it comes to -limitations on the number of segments being passed in. -This limit is -.B IOV_MAX -as defined in -.IR <limits.h> . -Currently, -.\" UIO_MAXIOV in kernel source -this limit is 1024. -.P -.\" commit 6a14b90bb6bc7cd83e2a444bf457a2ea645cbfe7 -.BR vmsplice () -really supports true splicing only from user memory to a pipe. -In the opposite direction, it actually just copies the data to user space. -But this makes the interface nice and symmetric and enables people to build on -.BR vmsplice () -with room for future improvement in performance. -.SH SEE ALSO -.BR splice (2), -.BR tee (2), -.BR pipe (7) |