1 .\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>
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25 .TH GETPAGESIZE 2 2010-11-16 "Linux" "Linux Programmer's Manual"
27 getpagesize \- get memory page size
29 .B #include <unistd.h>
31 .B int getpagesize(void);
34 Feature Test Macro Requirements for glibc (see
35 .BR feature_test_macros (7)):
46 !(_POSIX_C_SOURCE\ >=\ 200112L || _XOPEN_SOURCE\ >=\ 600)
50 _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
51 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
58 returns the number of bytes in a memory page,
59 where "page" is a fixed-length block,
60 the unit for memory allocation and file mapping performed by
63 .\" This call first appeared in 4.2BSD.
68 call is labeled LEGACY, and in POSIX.1-2001
70 HP-UX does not have this call.
72 Portable applications should employ
73 .I sysconf(_SC_PAGESIZE)
80 long sz = sysconf(_SC_PAGESIZE);
84 (Most systems allow the synonym
91 is present as a Linux system call depends on the architecture.
92 If it is, it returns the kernel symbol
94 whose value depends on the architecture and machine model.
95 Generally, one uses binaries that are dependent on the architecture but not
96 on the machine model, in order to have a single binary
97 distribution per architecture.
98 This means that a user program
101 at compile time from a header file,
102 but use an actual system call, at least for those architectures
103 (like sun4) where this dependency exists.
104 Here libc4, libc5, glibc 2.0 fail because their
106 returns a statically derived value, and does not use a system call.
107 Things are OK in glibc 2.1.
112 This page is part of release 3.65 of the Linux
115 A description of the project,
116 and information about reporting bugs,
118 \%http://www.kernel.org/doc/man\-pages/.