\"      $NetBSD: thrd.3,v 1.3 2019/04/27 10:57:11 wiz Exp $
\"
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\" This code is derived from software contributed to The NetBSD Foundation
\" by Kamil Rytarowski.
\"
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Dd October 16, 2016
Dt THRD 3
Os
Sh NAME
Nm thrd
Nd thread functions
Sh LIBRARY
Lb libpthread
Sh SYNOPSIS
In threads.h
Vt typedef "int" "(*thrd_start_t)" "(void *)"
Ft int
Fn thrd_create "thrd_t *thr" "thrd_start_t func" "void *arg"
Ft thrd_t
Fn thrd_current "void"
Ft int
Fn thrd_detach "thrd_t thr"
Ft int
Fn thrd_equal "thrd_t t1" "thrd_t t2"
Ft _Noreturn void
Fn thrd_exit "int res"
Ft int
Fn thrd_join "thrd_t thr" "int *res"
Ft int
Fn thrd_sleep "const struct timespec *duration" "struct timespec *remaining"
Ft void
Fn thrd_yield "void"
Sh DESCRIPTION
The
Nm
interface operates over opaque objects of the
Dv thrd_t
type.
Pp
The
Fn thrd_create
function is used to create a new thread, calling
Fa func
with the
Fa arg
parameter.
This function initializes the
Fa thr
object with the identifier of the newly created thread.
The completion of
Fn thrd_create
is synchronized with the start of the newly produced thread.
It is possible to reuse the
Fa thr
object once the thread has terminated either by joining another thread
operation or been detached.
Pp
The
Fn thrd_current
function returns the thread identifier of the current thread.
Pp
The
Fn thrd_detach
function is used to indicate that storage for the
Fa thr
object can be reclaimed on the thread's termination.
The
Fa thr
object cannot be already detached or joined.
Pp
The
Fn thrd_equal
function is used to check whether two
Fa t1
and
Fa t2
objects refer to the same thread.
Pp
The
Fn thrd_exit
function terminates the calling thread and passes the
Fa res
value that might be read by the
Fn thrd_join
function.
The program terminates once all threads have been terminated with
an exit code equivalent to calling the
Xr exit 3
function with the
Dv EXIT_SUCCESS
status.
The
Fn thrd_join
function joins the
Fa thr
thread, waiting and blocking until it has terminated.
The
Fa res
parameter points to a variable that will store the status passed from the
joined function.
If
Fa res
is
Dv NULL
then the status from the
Fn thrd_exit
function is ignored.
Pp
The
Fn thrd_sleep
function suspends execution of the calling thread until either
a signal is received or the interval specified in the
Fa duration
argument has been passed.
The
Fa remaining
parameter stores requested timeout reduced with the time actually suspended.
This argument is used when
Fn thrd_sleep
has been interrupted.
It is valid code to point both arguments
Fa duration
and
Fa remaining
to the same object.
It is not guaranteed that sleep will not take longer than specified in
Fa duration ,
however unless interrupted with a signal it will not take shorter
than the specified interval.
Pp
The
Fn thrd_yield
function yields a process voluntarily and gives other threads a chance to run
without waiting for any involuntary preemptive switch.
Sh RETURN VALUES
The
Fn thrd_create
function returns
Dv thrd_success
on success, otherwise
Dv thrd_nomem
if not sufficient memory could be allocated, or
Dv thrd_error
on other errors.
Pp
The
Fn thrd_current
function returns the identifier of the calling thread.
Pp
The
Fn thrd_detach
function returns
Dv thrd_current
on success or
Dv thrd_error
on failure.
Pp
The
Fn thrd_equal
function returns zero if
Fa t0
and
Fa t1
refer to the different threads,
otherwise it will return non-zero.
Pp
The
Fn thrd_exit
function does not return.
Pp
The
Fn thrd_join
function returns
Dv thrd_success
on success or
Dv thrd_error
on failure.
Pp
The
Fn thrd_sleep
function returns 0 on success (as the requested time has elapsed),
\-1 once the function was interrupted by a signal,
or a negative value to indicate error.
The
Nx
implementation returns \-2 on error.
Pp
The
Fn thrd_yield
function returns no value.
Sh SEE ALSO
Xr nanosleep 2 ,
Xr pthread_create 3 ,
Xr pthread_detach 3 ,
Xr pthread_equal 3 ,
Xr pthread_exit 3 ,
Xr pthread_join 3 ,
Xr pthread_self 3 ,
Xr sched 3 ,
Xr threads 3
Sh STANDARDS
The
Nm
interface conforms to
St -isoC-2011 .
Sh HISTORY
This interface first appeared in
Nx 9 .
Sh AUTHORS
An Kamil Rytarowski Aq Mt [email protected]

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