plucky (2) getpagesize.2.gz

NAME

       getpagesize - get memory page size

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <unistd.h>

       int getpagesize(void);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getpagesize():
           Since glibc 2.20:
               _DEFAULT_SOURCE || ! (_POSIX_C_SOURCE >= 200112L)
           glibc 2.12 to glibc 2.19:
               _BSD_SOURCE || ! (_POSIX_C_SOURCE >= 200112L)
           Before glibc 2.12:
               _BSD_SOURCE || _XOPEN_SOURCE >= 500

DESCRIPTION

       The  function  getpagesize() returns the number of bytes in a memory page, where "page" is a fixed-length
       block, the unit for memory allocation and file mapping performed by mmap(2).

VERSIONS

       A user program should not hard-code a page size, neither as a literal  nor  using  the  PAGE_SIZE  macro,
       because some architectures support multiple page sizes.

       This  manual  page  is  in  section  2  because  Alpha,  SPARC,  and SPARC64 all have a Linux system call
       getpagesize() though other architectures do not, and use the ELF auxiliary vector instead.

STANDARDS

       None.

HISTORY

       This call first appeared in 4.2BSD.  SVr4, 4.4BSD, SUSv2.  In SUSv2 the getpagesize()  call  was  labeled
       LEGACY, and it was removed in POSIX.1-2001.

       glibc 2.0 returned a constant even on architectures with multiple page sizes.

SEE ALSO

       mmap(2), sysconf(3)