개요

• 솔라나라에 설명된 어플리케이션에 대해 맨 페이지를 찾아 출력한다.
• MAN 페이지에 대한 설명은 윈디하나의 솔라나라: MAN 페이지을 참고하자.
• svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.

msync(2)

MSYNC(2)                   Linux Programmer's Manual                  MSYNC(2)

NAME
       msync - synchronize a file with a memory map

SYNOPSIS
       #include <sys/mman.h>

       int msync(void *addr, size_t length, int flags);

DESCRIPTION
       msync()  flushes  changes  made  to the in-core copy of a file that was
       mapped into memory using mmap(2) back to the filesystem.   Without  use
       of  this  call, there is no guarantee that changes are written back be‐
       fore munmap(2) is called.  To be more precise, the  part  of  the  file
       that  corresponds to the memory area starting at addr and having length
       length is updated.

       The flags argument should specify exactly one of MS_ASYNC and  MS_SYNC,
       and  may  additionally  include the MS_INVALIDATE bit.  These bits have
       the following meanings:

       MS_ASYNC
              Specifies that an update be scheduled, but the call returns  im‐
              mediately.

       MS_SYNC
              Requests an update and waits for it to complete.

       MS_INVALIDATE
              Asks to invalidate other mappings of the same file (so that they
              can be updated with the fresh values just written).

RETURN VALUE
       On  success,  zero is returned.  On error, -1 is returned, and errno is
       set appropriately.

ERRORS
       EBUSY  MS_INVALIDATE was specified in flags, and a memory  lock  exists
              for the specified address range.

       EINVAL addr  is  not  a  multiple  of  PAGESIZE;  or any bit other than
              MS_ASYNC | MS_INVALIDATE | MS_SYNC is  set  in  flags;  or  both
              MS_SYNC and MS_ASYNC are set in flags.

       ENOMEM The indicated memory (or part of it) was not mapped.

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

       This  call was introduced in Linux 1.3.21, and then used EFAULT instead
       of ENOMEM.  In Linux 2.4.19,  this  was  changed  to  the  POSIX  value
       ENOMEM.

AVAILABILITY
       On    POSIX    systems    on   which   msync()   is   available,   both
       _POSIX_MAPPED_FILES   and   _POSIX_SYNCHRONIZED_IO   are   defined   in
       <unistd.h> to a value greater than 0.  (See also sysconf(3).)

NOTES
       According  to  POSIX,  either  MS_SYNC or MS_ASYNC must be specified in
       flags, and indeed failure to include one  of  these  flags  will  cause
       msync()  to  fail  on  some  systems.  However, Linux permits a call to
       msync() that specifies neither of these flags, with semantics that  are
       (currently)  equivalent  to  specifying MS_ASYNC.  (Since Linux 2.6.19,
       MS_ASYNC is in fact a no-op, since the  kernel  properly  tracks  dirty
       pages  and  flushes them to storage as necessary.)  Notwithstanding the
       Linux behavior, portable, future-proof applications should ensure  that
       they specify either MS_SYNC or MS_ASYNC in flags.

SEE ALSO
       mmap(2)

       B.O. Gallmeister, POSIX.4, O'Reilly, pp. 128–129 and 389–391.

COLOPHON
       This  page  is  part of release 5.02 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
       https://www.kernel.org/doc/man-pages/.

Linux                             2017-09-15                          MSYNC(2)