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@(#)minherit.2 8.1 (Berkeley) 6/9/93
.Dd September 8, 2019 .Dt MINHERIT 2 .Os .Sh NAME .Nm minherit .Nd control the inheritance of pages .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/mman.h .Ft int .Fn minherit "void *addr" "size_t len" "int inherit" .Sh DESCRIPTION The .Fn minherit system call changes the specified range of virtual addresses to have the inheritance characteristic .Fa inherit , which determines how .Xr fork 2 will map the region in the child process. The supported inheritance characteristics are: l -tag -offset abcd -width MAP_INHERIT_DEFAULT t MAP_INHERIT_COPY The child is given a private copy of the region: writes from parent or child are not seen by the other. t MAP_INHERIT_NONE The region is unmapped in the child. t MAP_INHERIT_SHARE The child is shares the region with the parent: writes from parent and child are seen by both. t MAP_INHERIT_ZERO The region is mapped in the child to anonymous pages filled with zeros. .El
p Normally, the parent's virtual address space is copied for the child as if with .Dv MAP_INHERIT_COPY , for which the alias .Dv MAP_INHERIT_DEFAULT is provided. Regions in the parent mapped using .Xr mmap 2 with the .Dv MAP_SHARED flag are by default shared with the child as if with .Dv MAP_INHERIT_SHARED .
p 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. .Sh RETURN VALUES .Rv -std minherit .Sh ERRORS .Fn minherit will fail if: l -tag -width Er t Bq Er EINVAL An invalid region or invalid parameters were specified. .El .Sh SEE ALSO .Xr fork 2 , .Xr madvise 2 , .Xr mincore 2 , .Xr mmap 2 , .Xr mprotect 2 , .Xr msync 2 , .Xr munmap 2 .Sh HISTORY The .Fn minherit function first appeared in .Ox 2.0 , then .Nx 1.3 . .Sh 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 .Fn minherit .
Indexes created Wed Sep 24 05:09:52 GMT 2025