NAME
_lwp_create —
create a new light-weight
process
LIBRARY
library “libc”
SYNOPSIS
#include
<lwp.h>
int
_lwp_create(ucontext_t
*context, unsigned long
flags, lwpid_t
*new_lwp);
DESCRIPTION
_lwp_create()
causes creation of a new light-weight process, or LWP, and adds it to the
current process. The context argument specifies the
initial execution context for the new LWP including signal mask, stack, and
machine registers. The signal stack of the newly created light-weight process
is reset to disabled. 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.
The following flags affect the creation of the new LWP:
- 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 _lwp_wait(2).
- LWP_SUSPENDED
- The LWP is created suspended, and will not begin execution until it is resumed by another LWP via _lwp_continue(2).
The LWP ID of the new LWP is stored in the location pointed to by new_lwp.
RETURN VALUES
Upon successful completion, _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.
ERRORS
_lwp_create() will fail and no LWP will be
created if:
- [
EAGAIN] - The system-imposed limit on the total number of LWPs under execution would be exceeded. This limit is configuration-dependent.
- [
EFAULT] - The address pointed to by context or new_lwp is outside the process's allocated address space.
- [
EINVAL] - The ucontext_t passed is invalid.
- [
ENOMEM] - There is insufficient swap space for the new LWP.
SEE ALSO
_lwp_continue(2), _lwp_exit(2), _lwp_wait(2), _lwp_makecontext(3)
HISTORY
The _lwp_create() system call first
appeared in NetBSD 2.0.