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munmap(2)							    munmap(2)



NAME
  munmap - Unmaps a mapped region

SYNOPSIS

  #include <&lt;sys/mman.h>&gt;

  int munmap (
	  void *addr,
	  size_t len );

  [Tru64 UNIX]	The following definition of the	munmap() function does not
  conform to current standards and is supported	only for backward compatibil-
  ity (see standards(5)):


  #include <&lt;sys/mman.h>&gt;

  int munmap (
	  caddr_t addr,
	  size_t len );

STANDARDS

  Interfaces documented	on this	reference page conform to industry standards
  as follows:

  munmap():  XSH5.0

  Refer	to the standards(5) reference page for more information	about indus-
  try standards	and associated tags.

PARAMETERS

  addr	    Specifies the address of the region	to be unmapped.

  len	    Specifies the length in bytes of the region	to be unmapped.

DESCRIPTION

  The munmap() function	unmaps a mapped	file or	shared memory region.

  The addr and len parameters specify the address and length in	bytes,
  respectively,	of the region to be unmapped.  The len parameter must be a
  multiple of the page size as returned	by sysconf(_SC_PAGE_SIZE).  If len is
  not a	multiple of the	page size as returned by sysconf(_SC_PAGE_SIZE), the
  length of the	region will be rounded up to the next multiple of the page
  size.

  The result of	using an address which lies in an unmapped region and not in
  any subsequently mapped region is undefined.


RETURN VALUES

  Upon successful completion, the munmap() function returns 0 (zero).  Other-
  wise,	munmap() returns -1 and	sets errno to indicate the error.


ERRORS

  If the munmap() function fails, errno	may be set to one of the following
  values:

  [EFAULT]  The	range [addr, addr + len) includes an invalid address.

  [EINVAL]  The	addr parameter is not a	multiple of the	page size as returned
	    by sysconf(_SC_PAGE_SIZE).

	    The	len parameter is 0 (zero).

RELATED	INFORMATION

  Functions: mmap(2), sysconf(3)

  Standards: standards(5)