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[;1m-spec erlang:suspend_process(Suspendee, OptList) -> boolean()[0m
[;1m when[0m
[;1m Suspendee :: pid(),[0m
[;1m OptList :: [Opt],[0m
[;1m Opt ::[0m
[;1m unless_suspending |[0m
[;1m asynchronous |[0m
[;1m {asynchronous, term()}.[0m
Increases the suspend count on the process identified by [;;4m[0m
[;;4mSuspendee[0m and puts it in the suspended state if it is not already
in that state. A suspended process is not scheduled for execution
until the process has been resumed.
A process can be suspended by multiple processes and can be
suspended multiple times by a single process. A suspended process
does not leave the suspended state until its suspend count reaches
zero. The suspend count of [;;4mSuspendee[0m is decreased when [;;4m[0m
[;;4merlang:resume_process(Suspendee)[0m is called by the same process
that called [;;4merlang:suspend_process(Suspendee)[0m. All increased
suspend counts on other processes acquired by a process are
automatically decreased when the process terminates.
Options ([;;4mOpt[0ms):
[;;4m[;;4masynchronous[0m[0m:
A suspend request is sent to the process identified by [;;4m[0m
[;;4mSuspendee[0m. [;;4mSuspendee[0m eventually suspends unless it is
resumed before it could suspend. The caller of [;;4m[0m
[;;4merlang:suspend_process/2[0m returns immediately, regardless of
whether [;;4mSuspendee[0m has suspended yet or not. The point in
time when [;;4mSuspendee[0m suspends cannot be deduced from other
events in the system. It is only guaranteed that [;;4mSuspendee[0m
eventually suspends (unless it is resumed). If no [;;4m[0m
[;;4masynchronous[0m options has been passed, the caller of [;;4m[0m
[;;4merlang:suspend_process/2[0m is blocked until [;;4mSuspendee[0m has
suspended.
[;;4m[;;4m{asynchronous, ReplyTag}[0m[0m:
A suspend request is sent to the process identified by [;;4m[0m
[;;4mSuspendee[0m. When the suspend request has been processed, a
reply message is sent to the caller of this function. The
reply is on the form [;;4m{ReplyTag, State}[0m where [;;4mState[0m is
either:
[;;4m[;;4mexited[0m[0m:
[;;4mSuspendee[0m has exited.
[;;4m[;;4msuspended[0m[0m:
[;;4mSuspendee[0m is now suspended.
[;;4m[;;4mnot_suspended[0m[0m:
[;;4mSuspendee[0m is not suspended. This can only happen when the
process that issued this request, have called [;;4m[0m
[;;4mresume_process(Suspendee)[0m before getting the reply.
Appart from the reply message, the [;;4m{asynchronous, ReplyTag}[0m
option behaves exactly the same as the [;;4masynchronous[0m option
without reply tag.
[;;4m[;;4munless_suspending[0m[0m:
The process identified by [;;4mSuspendee[0m is suspended unless the
calling process already is suspending [;;4mSuspendee[0m. If [;;4m[0m
[;;4munless_suspending[0m is combined with option [;;4masynchronous[0m, a
suspend request is sent unless the calling process already is
suspending [;;4mSuspendee[0m or if a suspend request already has
been sent and is in transit. If the calling process already is
suspending [;;4mSuspendee[0m, or if combined with option [;;4m[0m
[;;4masynchronous[0m and a send request already is in transit, [;;4mfalse[0m
is returned and the suspend count on [;;4mSuspendee[0m remains
unchanged.
If the suspend count on the process identified by [;;4mSuspendee[0m is
increased, [;;4mtrue[0m is returned, otherwise [;;4mfalse[0m.
Warning:
This BIF is intended for debugging only.
Warning:
You can easily create deadlocks if processes suspends each
other (directly or in circles). In ERTS versions prior to ERTS
version 10.0, the runtime system prevented such deadlocks, but
this prevention has now been removed due to performance
reasons.
Failures:
[;;4m[;;4mbadarg[0m[0m:
If [;;4mSuspendee[0m is not a process identifier.
[;;4m[;;4mbadarg[0m[0m:
If the process identified by [;;4mSuspendee[0m is the same process
as the process calling [;;4merlang:suspend_process/2[0m.
[;;4m[;;4mbadarg[0m[0m:
If the process identified by [;;4mSuspendee[0m is not alive.
[;;4m[;;4mbadarg[0m[0m:
If the process identified by [;;4mSuspendee[0m resides on another
node.
[;;4m[;;4mbadarg[0m[0m:
If [;;4mOptList[0m is not a proper list of valid [;;4mOpt[0ms.
[;;4m[;;4msystem_limit[0m[0m:
If the process identified by [;;4mSuspendee[0m has been suspended
more times by the calling process than can be represented by
the currently used internal data structures. The system limit
is greater than 2,000,000,000 suspends and will never be
lower.
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