netbsd man page for minherit

MINHERIT(2)						      BSD System Calls Manual						       MINHERIT(2)

NAME
     minherit -- control the inheritance of pages

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/mman.h>

     int
     minherit(void *addr, size_t len, int inherit);

DESCRIPTION
     The minherit() system call changes the specified range of virtual addresses to have the specified fork-time inheritance characteristic
     inherit, which can be set to MAP_INHERIT_NONE, MAP_INHERIT_COPY, or MAP_INHERIT_SHARE.  Also possible is MAP_INHERIT_DEFAULT, which defaults
     to MAP_INHERIT_COPY.  Not all implementations will guarantee that the inheritance characteristic can be set on a page basis; the granularity
     of changes may be as large as an entire region.

     Normally, the entire address space is marked MAP_INHERIT_COPY; when the process calls fork(), the child receives a (virtual) copy of the
     entire address space.  Pages or regions marked MAP_INHERIT_SHARE are shared between the address spaces, while pages or regions marked
     MAP_INHERIT_NONE will be unmapped in the child.

RETURN VALUES
     The minherit() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indi-
     cate the error.

ERRORS
     minherit() will fail if:

     [EINVAL]		An invalid region or invalid parameters were specified.

SEE ALSO
     fork(2), madvise(2), mincore(2), mprotect(2), msync(2), munmap(2)

HISTORY
     The minherit() function first appeared in OpenBSD.

BUGS
     If a particular port does not support page-granularity inheritance, there's no way to figure out how large a region is actually affected by
     minherit().

BSD
								  October 7, 2006							       BSD