text: The following form allows you to view linux man pages.
  #include <sys/mman.h>
  void *mmap(void *addr, size_t length, int prot, int flags,
  int fd, off_t offset);
  int munmap(void *addr, size_t length);
  See NOTES for information on feature test macro requirements.
  mmap() creates a new mapping in the virtual address space of the call-
  ing process. The starting address for the new mapping is specified in
  addr. The length argument specifies the length of the mapping.
  If addr is NULL, then the kernel chooses the address at which to create
  the mapping; this is the most portable method of creating a new map-
  ping. map-
  ping  visi-
  ble map-
  context-switch performance on some early 64-bit processors.
  Modern x86-64 processors no longer have this performance prob-
  lem, so use of this flag is not required on those systems. The
  MAP_32BIT flag is ignored when MAP_FIXED is set.
  MAP_ANON
  Synonym for MAP_ANONYMOUS. Deprecated.
  MAP_ANONYMOUS
  The mapping is not backed by any file; its contents are initial-
  ized dis-
  couraged. infor-
  mation.
  MAP_LOCKED (since Linux 2.5.37)
  Lock the pages of the mapped region into memory in the manner of
  mlock(2). This flag is ignored in older kernels.
  MAP_NONBLOCK (since Linux 2.5.46)
  Only meaningful in conjunction with MAP_POPULATE. Don't perform
  MAP_POPULATE (since Linux 2.5.46)
  Populate (prefault) page tables for a mapping. For a file map-
  ping,_UNINITIAL-
  IZED option. Because of the security implications, that option
  is normally enabled only on embedded devices (i.e., devices
  where one has complete control of the contents of user memory).
  Of the above flags, only MAP_FIXED is specified in POSIX.1-2001. How-
  ever,. All pages con-
  taining a part of the indicated range are unmapped, and subsequent ref-
  erences to these pages will generate SIGSEGV. It is not an error if
  the indicated range does not contain any mapped pages.
  Timestamps changes for file-backed mappings
  For file-backed mappings, the st_atime field for the mapped file may be map-
  pings would have been exceeded.
  EPERM The prot argument asks for PROT_EXEC but the mapped area belongs
  to a file on a filesystem that was mounted no-exec. corre-
  spond to the file (for example, beyond the end of the file,
  including the case where another process has truncated the
  mmap2(2), and nowadays the glibc mmap() wrapper function invokes
  mmap2(2) with a suitably adjusted value for offset. modifica-
  tion call-
  ing msync(2) before the unmap takes place; however, this doesn't work
  on tmpfs (for example, when using POSIX shared memory interface docu-
  mented in shm_overview(7)).
  The following program prints part of the file specified in its first
  command-line argument to standard output. The range of bytes to be
  printed is specified via offset and length values in the second and
  third command-line arguments. The program creates a memory mapping of");
  B.O. Gallmeister, POSIX.4, O'Reilly, pp. 128-129 and 389-391.
  webmaster@linuxguruz.com