execve.2, exec.3: Consistently use the term 'pathname' (not 'path')

[thirdparty/man-pages.git] / man2 / posix_fadvise.2

diff --git a/man2/posix_fadvise.2 b/man2/posix_fadvise.2
index 5ead8c6e100d66c17ca185fdcb8f9d1674ccc8c0..00adb62d60c56a9c6fe2c6bd91413e9c26951d68 100644 (file)
--- a/man2/posix_fadvise.2
+++ b/man2/posix_fadvise.2
@@ -26,23 +26,23 @@
 .\" 2005-04-08 mtk, noted kernel version and added BUGS
 .\" 2010-10-09, mtk, document arm_fadvise64_64()
 .\"
-.TH POSIX_FADVISE 2 2016-03-15 "Linux" "Linux Programmer's Manual"
+.TH POSIX_FADVISE 2 2019-03-06 "Linux" "Linux Programmer's Manual"
 .SH NAME
 posix_fadvise \- predeclare an access pattern for file data
 .SH SYNOPSIS
 .nf
 .B #include <fcntl.h>
-.sp
+.PP
 .BI "int posix_fadvise(int " fd ", off_t " offset ", off_t " len \
 ", int " advice ");"
 .fi
-.sp
+.PP
 .ad l
 .in -4n
 Feature Test Macro Requirements for glibc (see
 .BR feature_test_macros (7)):
 .in
-.sp
+.PP
 .BR posix_fadvise ():
 .RS 4
 _POSIX_C_SOURCE\ >=\ 200112L
@@ -54,14 +54,14 @@ Programs can use
 to announce an intention to access
 file data in a specific pattern in the future, thus allowing the kernel
 to perform appropriate optimizations.
-
+.PP
 The \fIadvice\fP applies to a (not necessarily existent) region starting
 at \fIoffset\fP and extending for \fIlen\fP bytes (or until the end of
 the file if \fIlen\fP is 0) within the file referred to by \fIfd\fP.
 The \fIadvice\fP is not binding;
 it merely constitutes an expectation on behalf of
 the application.
-
+.PP
 Permissible values for \fIadvice\fP include:
 .TP
 .B POSIX_FADV_NORMAL
@@ -79,14 +79,14 @@ The specified data will be accessed in random order.
 .TP
 .B POSIX_FADV_NOREUSE
 The specified data will be accessed only once.
-
+.IP
 In kernels before 2.6.18, \fBPOSIX_FADV_NOREUSE\fP had the
 same semantics as \fBPOSIX_FADV_WILLNEED\fP.
 This was probably a bug; since kernel 2.6.18, this flag is a no-op.
 .TP
 .B POSIX_FADV_WILLNEED
 The specified data will be accessed in the near future.
-
+.IP
 \fBPOSIX_FADV_WILLNEED\fP initiates a
 nonblocking read of the specified region into the page cache.
 The amount of data read may be decreased by the kernel depending
@@ -96,7 +96,7 @@ and more is rarely useful.)
 .TP
 .B POSIX_FADV_DONTNEED
 The specified data will not be accessed in the near future.
-
+.IP
 \fBPOSIX_FADV_DONTNEED\fP attempts to free cached pages associated with
 the specified region.
 This is useful, for example, while streaming large
@@ -104,7 +104,7 @@ files.
 A program may periodically request the kernel to free cached data
 that has already been used, so that more useful cached pages are not
 discarded instead.
-
+.IP
 Requests to discard partial pages are ignored.
 It is preferable to preserve needed data than discard unneeded data.
 If the application requires that data be considered for discarding, then
@@ -112,7 +112,7 @@ If the application requires that data be considered for discarding, then
 and
 .I len
 must be page-aligned.
-
+.IP
 The implementation
 .I may
 attempt to write back dirty pages in the specified region,
@@ -152,7 +152,7 @@ the underlying system call is called
 Library support has been provided since glibc version 2.2,
 via the wrapper function
 .BR posix_fadvise ().
-
+.PP
 Since Linux 3.18,
 .\" commit d3ac21cacc24790eb45d735769f35753f5b56ceb
 support for the underlying system call is optional,
@@ -174,12 +174,12 @@ default size for the backing device; \fBPOSIX_FADV_SEQUENTIAL\fP doubles
 this size, and \fBPOSIX_FADV_RANDOM\fP disables file readahead entirely.
 These changes affect the entire file, not just the specified region
 (but other open file handles to the same file are unaffected).
-
+.PP
 The contents of the kernel buffer cache can be cleared via the
 .IR /proc/sys/vm/drop_caches
 interface described in
 .BR proc (5).
-
+.PP
 One can obtain a snapshot of which pages of a file are resident
 in the buffer cache by opening a file, mapping it with
 .BR mmap (2),
@@ -192,7 +192,10 @@ The name of the wrapper function in the C library is
 The underlying system call is called
 .BR fadvise64 ()
 (or, on some architectures,
-.BR fadvise64_64 ()).
+.BR fadvise64_64 ());
+the difference between the two is that the former system call
+assumes that the type of the \fIlen\fP argument is \fIsize_t\fP,
+while the latter expects \fIloff_t\fP there.
 .SS Architecture-specific variants
 Some architectures require
 64-bit arguments to be aligned in a suitable pair of registers (see
@@ -210,14 +213,14 @@ Therefore, these architectures define a version of the
 system call that orders the arguments suitably,
 but is otherwise exactly the same as
 .BR posix_fadvise ().
-
+.PP
 For example, since Linux 2.6.14, ARM has the following system call:
 .PP
 .in +4n
-.nf
+.EX
 .BI "long arm_fadvise64_64(int " fd ", int " advice ,
 .BI "                      loff_t " offset ", loff_t " len );
-.fi
+.EE
 .in
 .PP
 These architecture-specific details are generally
@@ -231,6 +234,7 @@ In kernels before 2.6.6, if
 was specified as 0, then this was interpreted literally as "zero bytes",
 rather than as meaning "all bytes through to the end of the file".
 .SH SEE ALSO
+.BR fincore (1),
 .BR mincore (2),
 .BR readahead (2),
 .BR sync_file_range (2),