NAME
_lwp_create —
create a new light-weight
process
LIBRARY
Standard C Library (libc, -lc)
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.