Provided by: manpages-dev_4.04-2_all bug


       getpagesize - get memory page size


       #include <unistd.h>

       int getpagesize(void);

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

           Since glibc 2.12:
               _BSD_SOURCE ||
                   !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
           Before glibc 2.12:


       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).


       SVr4, 4.4BSD,  SUSv2.   In  SUSv2  the  getpagesize()  call  is  labeled  LEGACY,  and  in
       POSIX.1-2001 it has been dropped; HP-UX does not have this call.


       Portable applications should employ sysconf(_SC_PAGESIZE) instead of getpagesize():

           #include <unistd.h>
           long sz = sysconf(_SC_PAGESIZE);

       (Most systems allow the synonym _SC_PAGE_SIZE for _SC_PAGESIZE.)

       Whether  getpagesize()  is present as a Linux system call depends on the architecture.  If
       it is, it returns the kernel symbol PAGE_SIZE, whose value depends on the architecture and
       machine  model.   Generally,  one uses binaries that are dependent on the architecture but
       not on the machine model, in order to have a single binary distribution per  architecture.
       This  means  that  a  user program should not find PAGE_SIZE at compile time from a header
       file, but use an actual system call, at least for those architectures  (like  sun4)  where
       this  dependency  exists.   Here  glibc  2.0  fails  because  its  getpagesize() returns a
       statically derived value, and does not use a system call.  Things are OK in glibc 2.1.


       mmap(2), sysconf(3)


       This page is part of release 4.04 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at