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by Jason R. Thorpe of Wasabi Systems, Inc.
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.Dd January 13, 2003 .Dt _LWP_CREATE 2 .Os .Sh NAME .Nm _lwp_create .Nd create a new light-weight process .Sh LIBRARY .Lb libc .Sh SYNOPSIS n lwp.h .Ft int .Fn _lwp_create "ucontext_t *context" "unsigned long flags" "lwpid_t *new_lwp" .Sh DESCRIPTION .Fn _lwp_create causes creation of a new light-weight process, or LWP, and adds it to the current process. The .Fa context argument specifies the initial execution context for the new LWP including signal mask, stack, and machine registers. If this context specifies invalid register values (for example priviledge escalation by setting machine dependend bits forbidden for user processes), or does not specify cpu register values (uc_flags does not have the _UC_CPU bit set), the call will fail and errno will be set to EINVAL.
p
The following flags affect the creation of the new LWP:
l -tag -width LWP_SUSPENDED t LWP_DETACHED The LWP is created detached.
The resources associated with a detached LWP will be automatically
reclaimed by the system when the LWP exits.
Otherwise, a terminated LWP's resources will not be reclaimed until
its status is reported to another LWP via
.Xr _lwp_wait 2 .
t LWP_SUSPENDED The LWP is created suspended, and will not begin execution until
it is resumed by another LWP via
.Xr _lwp_continue 2 .
__LWP_ASLWP is not yet implemented by the NetBSD kernel.
.El
p The LWP ID of the new LWP is stored in the location pointed to by .Fa new_lwp . .Sh RETURN VALUES Upon successful completion, .Fn _lwp_create returns a value of 0. Otherwise, a value of -1 is returned and errno is set to one of the values documented below. .Sh ERRORS .Fn _lwp_create will fail and no LWP will be created if: l -tag -width [EAGAIN] t Bq Er EAGAIN The system-imposed limit on the total number of LWPs under execution would be exceeded. This limit is configuration-dependent. t Bq Er ENOMEM There is insufficient swap space for the new LWP. t Bq Er EFAULT The address pointed to by .Fa context or .Fa new_lwp is outside the process's allocated address space. t Bq Er EINVAL The ucontext_t passed is invalid. .El .Sh SEE ALSO .Xr _lwp_continue 2 , .Xr _lwp_exit 2 , .Xr _lwp_wait 2 , .Xr _lwp_makecontext 3 .Sh HISTORY The .Fn _lwp_create system call first appeared in .Nx 2.0 .