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lib/libc/sys/minherit.2
| Show All 23 Lines | |||||
| .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||||
| .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | ||||
| .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | ||||
| .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | ||||
| .\" SUCH DAMAGE. | .\" SUCH DAMAGE. | ||||
| .\" | .\" | ||||
| .\" @(#)minherit.2 8.1 (Berkeley) 6/9/93 | .\" @(#)minherit.2 8.1 (Berkeley) 6/9/93 | ||||
| .\" | .\" | ||||
| .Dd October 30, 2007 | .Dd March 15, 2017 | ||||
| .Dt MINHERIT 2 | .Dt MINHERIT 2 | ||||
| .Os | .Os | ||||
| .Sh NAME | .Sh NAME | ||||
| .Nm minherit | .Nm minherit | ||||
| .Nd control the inheritance of pages | .Nd control the inheritance of pages | ||||
| .Sh LIBRARY | .Sh LIBRARY | ||||
| .Lb libc | .Lb libc | ||||
| .Sh SYNOPSIS | .Sh SYNOPSIS | ||||
| ▲ Show 20 Lines • Show All 45 Lines • ▼ Show 20 Lines | |||||
| This option also has an unfortunate side effect of causing the parent | This option also has an unfortunate side effect of causing the parent | ||||
| address space to become copy-on-write when the parent forks. | address space to become copy-on-write when the parent forks. | ||||
| If the original mapping was | If the original mapping was | ||||
| .Dv MAP_SHARED , | .Dv MAP_SHARED , | ||||
| it will no longer be shared in the parent | it will no longer be shared in the parent | ||||
| after the parent forks and there is no way to get the previous | after the parent forks and there is no way to get the previous | ||||
| shared-backing-store mapping without unmapping and remapping the address | shared-backing-store mapping without unmapping and remapping the address | ||||
| space in the parent. | space in the parent. | ||||
| .It Dv INHERIT_ZERO | |||||
| This option causes the address space in question to be mapped as new | |||||
| anonymous pages, | |||||
| which would be initialized to all zero bytes, | |||||
| in the child process. | |||||
| .El | .El | ||||
| .Sh RETURN VALUES | .Sh RETURN VALUES | ||||
| .Rv -std minherit | .Rv -std minherit | ||||
| .Sh ERRORS | .Sh ERRORS | ||||
| The | The | ||||
| .Fn minherit | .Fn minherit | ||||
| system call will fail if: | system call will fail if: | ||||
| .Bl -tag -width Er | .Bl -tag -width Er | ||||
| Show All 23 Lines | |||||
| .Xr rfork 2 | .Xr rfork 2 | ||||
| .Sh HISTORY | .Sh HISTORY | ||||
| The | The | ||||
| .Fn minherit | .Fn minherit | ||||
| system call first appeared in | system call first appeared in | ||||
| .Ox | .Ox | ||||
| and then in | and then in | ||||
| .Fx 2.2 . | .Fx 2.2 . | ||||
| .Pp | |||||
| The | |||||
| .Dv INHERIT_ZERO | |||||
| support first appeared in | |||||
| .Ox 5.6 | |||||
| and then in | |||||
| .Fx 12.0 . | |||||
| .Sh BUGS | .Sh BUGS | ||||
| Once you set inheritance to | Once you set inheritance to | ||||
| .Dv MAP_PRIVATE | .Dv MAP_PRIVATE | ||||
| or | or | ||||
| .Dv MAP_SHARED , | .Dv MAP_SHARED , | ||||
| there is no way to recover the original copy-on-write semantics | there is no way to recover the original copy-on-write semantics | ||||
| short of unmapping and remapping the area. | short of unmapping and remapping the area. | ||||