- NetBSD Manual Pages
_LWP_CREATE(2) NetBSD System Calls Manual _LWP_CREATE(2)
Powered by man-cgi (2021-03-02).
Maintained for NetBSD
by Kimmo Suominen.
Based on man-cgi by Panagiotis Christias.
_lwp_create -- create a new light-weight process
Standard C Library (libc, -lc)
_lwp_create(ucontext_t *context, unsigned long flags, lwpid_t *new_lwp);
_lwp_create() causes creation of a new light-weight process, or LWP, and
adds it to the current process. The context argument specifies the ini-
tial 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 val-
ues (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
Upon successful completion, _lwp_create() returns a value of 0. Other-
wise, a value of -1 is returned and errno is set to one of the values
_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-
[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.
_lwp_continue(2), _lwp_exit(2), _lwp_wait(2), _lwp_makecontext(3)
The _lwp_create() system call first appeared in NetBSD 2.0.
NetBSD 9.99 April 21, 2017 NetBSD 9.99