Differential D19058 Diff 62564 head/lib/libc/sys/rfork.2

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head/lib/libc/sys/rfork.2

	.\"			.\"
	.\" This manual page is taken directly from Plan9, and modified to			.\" This manual page is taken directly from Plan9, and modified to
	.\" describe the actual BSD implementation. Permission for			.\" describe the actual BSD implementation. Permission for
	.\" use of this page comes from Rob Pike <rob@plan9.att.com>.			.\" use of this page comes from Rob Pike <rob@plan9.att.com>.
	.\"			.\"
	.\" $FreeBSD$			.\" $FreeBSD$
	.\"			.\"
	.Dd July 12, 2011			.Dd September 25, 2019
	.Dt RFORK 2			.Dt RFORK 2
	.Os			.Os
	.Sh NAME			.Sh NAME
	.Nm rfork			.Nm rfork
	.Nd manipulate process resources			.Nd manipulate process resources
	.Sh LIBRARY			.Sh LIBRARY
	.Lb libc			.Lb libc
	.Sh SYNOPSIS			.Sh SYNOPSIS
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	their default values.			their default values.
	The resources include			The resources include
	the open file descriptor table (which, when shared, permits processes			the open file descriptor table (which, when shared, permits processes
	to open and close files for other processes),			to open and close files for other processes),
	and open files.			and open files.
	The			The
	.Fa flags			.Fa flags
	argument			argument
	is the logical OR of some subset of:			is either
				.Dv RFSPAWN
				or the logical OR of some subset of:
	.Bl -tag -width ".Dv RFLINUXTHPN"			.Bl -tag -width ".Dv RFLINUXTHPN"
	.It Dv RFPROC			.It Dv RFPROC
	If set a new process is created; otherwise changes affect the			If set a new process is created; otherwise changes affect the
	current process.			current process.
	.It Dv RFNOWAIT			.It Dv RFNOWAIT
	If set, the child process will be dissociated from the parent.			If set, the child process will be dissociated from the parent.
	Upon			Upon
	exit the child will not leave a status for the parent to collect.			exit the child will not leave a status for the parent to collect.
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	If set, the kernel will deliver SIGUSR1 instead of SIGCHLD upon thread			If set, the kernel will deliver SIGUSR1 instead of SIGCHLD upon thread
	exit for the child.			exit for the child.
	This is intended to mimic certain Linux clone behaviour.			This is intended to mimic certain Linux clone behaviour.
	.El			.El
	.Pp			.Pp
	File descriptors in a shared file descriptor table are kept			File descriptors in a shared file descriptor table are kept
	open until either they are explicitly closed			open until either they are explicitly closed
	or all processes sharing the table exit.			or all processes sharing the table exit.
				.Pp
				If
				.Dv RFSPAWN
				is passed,
				.Nm
				will use
				.Xr vfork 2
				semantics but reset all signal actions in the child to default.
	.Pp			.Pp
	If			If
	.Dv RFPROC			.Dv RFPROC
	is set, the			is set, the
	value returned in the parent process			value returned in the parent process
	is the process id			is the process id
	of the child process; the value returned in the child is zero.			of the child process; the value returned in the child is zero.
	Without			Without
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