1.\" $NetBSD: _lwp_create.2,v 1.11 2022/12/04 16:17:50 uwe 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 privilege 53escalation by setting machine dependent bits forbidden for user processes), 54or does not specify cpu register values 55.Fa ( uc_flags 56does not have the 57.Dv _UC_CPU 58bit set), the call will fail and errno will be set to 59.Er EINVAL . 60.Pp 61The following flags affect the creation of the new LWP: 62.Bl -tag -width Dv 63.It Dv LWP_DETACHED 64The LWP is created detached. 65The resources associated with a detached LWP will be automatically 66reclaimed by the system when the LWP exits. 67Otherwise, a terminated LWP's resources will not be reclaimed until 68its status is reported to another LWP via 69.Xr _lwp_wait 2 . 70.It Dv LWP_SUSPENDED 71The LWP is created suspended, and will not begin execution until 72it is resumed by another LWP via 73.Xr _lwp_continue 2 . 74.\" __LWP_ASLWP is not yet implemented by the NetBSD kernel. 75.El 76.Pp 77The LWP ID of the new LWP is stored in the location pointed to by 78.Fa new_lwp . 79.Sh RETURN VALUES 80.Rv -std _lwp_create 81.Sh ERRORS 82.Fn _lwp_create 83will fail and no LWP will be created if: 84.Bl -tag -width Er 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 97.Vt ucontext_t 98passed is invalid. 99.It Bq Er ENOMEM 100There is insufficient swap space for the new LWP. 101.El 102.Sh SEE ALSO 103.Xr _lwp_continue 2 , 104.Xr _lwp_exit 2 , 105.Xr _lwp_wait 2 , 106.Xr _lwp_makecontext 3 107.Sh HISTORY 108The 109.Fn _lwp_create 110system call first appeared in 111.Nx 2.0 . 112