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35 .\" @(#)minherit.2 8.1 (Berkeley) 6/9/93
42 .Nd control the inheritance of pages
49 .Fn minherit "void *addr" "size_t len" "int inherit"
54 changes the specified pages to have the inheritance characteristic
56 Not all implementations will guarantee that the inheritance characteristic
57 can be set on a page basis;
58 the granularity of changes may be as large as an entire region.
60 is capable of adjusting inheritance characteristics on a page basis.
61 Inheritance only effects children created by
65 exec'd processes replace their address space entirely.
67 has no effect on the parent's address space (other than to potentially
68 share the address space with its children).
70 Inheritance is a rather esoteric feature largely superseded by the
74 However, it is possible to use
76 to share a block of memory between parent and child that has been mapped
78 That is, modifications made by parent or child are shared but
79 the original underlying file is left untouched.
80 .Bl -tag -width ".Dv INHERIT_SHARE"
82 This option causes the address space in question to be shared between
84 It has no effect on how the original underlying backing
87 This option prevents the address space in question from being inherited
89 The address space will be unmapped in the child.
91 This option causes the child to inherit the address space as copy-on-write.
92 This option also has an unfortunate side effect of causing the parent
93 address space to become copy-on-write when the parent forks.
94 If the original mapping was
96 it will no longer be shared in the parent
97 after the parent forks and there is no way to get the previous
98 shared-backing-store mapping without unmapping and remapping the address
106 function will fail if:
109 The virtual address range specified by the
113 arguments is not valid.
115 The flags specified by the
117 argument were not valid for the pages specified
135 function first appeared in