1.\" $NetBSD: _lwp_create.2,v 1.7 2017/04/23 11:38:53 wiz Exp $ 2.\" 3.\" Copyright (c) 2003 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Jason R. Thorpe of Wasabi Systems, Inc. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd April 21, 2017 31.Dt _LWP_CREATE 2 32.Os 33.Sh NAME 34.Nm _lwp_create 35.Nd create a new light-weight process 36.Sh LIBRARY 37.Lb libc 38.Sh SYNOPSIS 39.In lwp.h 40.Ft int 41.Fn _lwp_create "ucontext_t *context" "unsigned long flags" "lwpid_t *new_lwp" 42.Sh DESCRIPTION 43.Fn _lwp_create 44causes creation of a new light-weight process, or LWP, and adds it to the 45current process. 46The 47.Fa context 48argument specifies the initial execution context for the new LWP including 49signal mask, stack, and machine registers. 50The signal stack of the newly created light-weight process is reset to 51disabled. 52If this context specifies invalid register values (for example priviledge 53escalation by setting machine dependend bits forbidden for user processes), 54or does not specify cpu register values (uc_flags does not have the 55_UC_CPU bit set), the call will fail and errno will be set to EINVAL. 56.Pp 57The following flags affect the creation of the new LWP: 58.Bl -tag -width LWP_SUSPENDED 59.It LWP_DETACHED 60The LWP is created detached. 61The resources associated with a detached LWP will be automatically 62reclaimed by the system when the LWP exits. 63Otherwise, a terminated LWP's resources will not be reclaimed until 64its status is reported to another LWP via 65.Xr _lwp_wait 2 . 66.It LWP_SUSPENDED 67The LWP is created suspended, and will not begin execution until 68it is resumed by another LWP via 69.Xr _lwp_continue 2 . 70.\" __LWP_ASLWP is not yet implemented by the NetBSD kernel. 71.El 72.Pp 73The LWP ID of the new LWP is stored in the location pointed to by 74.Fa new_lwp . 75.Sh RETURN VALUES 76Upon successful completion, 77.Fn _lwp_create 78returns a value of 0. 79Otherwise, a value of -1 is returned and errno is set to one of the values 80documented below. 81.Sh ERRORS 82.Fn _lwp_create 83will fail and no LWP will be created if: 84.Bl -tag -width 10n 85.It Bq Er EAGAIN 86The system-imposed limit on the total 87number of LWPs under execution would be exceeded. 88This limit is configuration-dependent. 89.It Bq Er EFAULT 90The address pointed to by 91.Fa context 92or 93.Fa new_lwp 94is outside the process's allocated address space. 95.It Bq Er EINVAL 96The ucontext_t passed is invalid. 97.It Bq Er ENOMEM 98There is insufficient swap space for the new LWP. 99.El 100.Sh SEE ALSO 101.Xr _lwp_continue 2 , 102.Xr _lwp_exit 2 , 103.Xr _lwp_wait 2 , 104.Xr _lwp_makecontext 3 105.Sh HISTORY 106The 107.Fn _lwp_create 108system call first appeared in 109.Nx 2.0 . 110