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mvalid(2)							    mvalid(2)



NAME
  mvalid - Checks memory region	for validity

SYNOPSIS

  #include <&lt;sys/types.h>&gt;
  #include <&lt;sys/mman.h>&gt;
  int mvalid (
	  caddr_t addr,
	  size_t len,
	  int prot  );

PARAMETERS

  addr	    Specifies the address of the region	whose validity is to be
	    checked.

  len	    Specifies length in	bytes of the region specified by the addr
	    parameter.

  prot	    Specifies the desired access protection for	the region.

DESCRIPTION

  The mvalid() function	checks the validity of a memory	region.	 A region is
  considered to	be valid if accesses of	the requested type are allowed to all
  addresses in the region.

  The sys/mman.h header	file defines the following access options:

  PROT_READ The	mapped region can be read.

  PROT_WRITE
	    The	mapped region can be written.

  PROT_EXEC The	mapped region can be executed.

  The prot parameter can be any	combination of PROT_READ, PROT_WRITE, and
  PROT_EXEC ORed together.

RETURN VALUES

  The mvalid() function	returns	0 (zero) if accesses requiring the specified
  protection are allowed to all	addresses within the specified range of
  addresses.  Otherwise, the mvalid() function returns -1 and sets errno to
  indicate the error.

ERRORS

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

  [EACCES]  The	range specified	by [addr, addr + len) is invalid for the
	    process' address space, or the range specifies one or more
	    unmapped pages, or one or more pages of the	range disallows
	    accesses of	the specified protection.

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

RELATED	INFORMATION

  Functions: mmap(2), mprotect(2), sysconf(3)