Quelle syncvars.xml Sprache: XML

<Chapter Label="Synchronization variables">
  <Heading>Synchronization variables</Heading>

<Section Label="section:Synchronization variables">
  <Heading>Synchronization variables</Heading>

Synchronization variables (also often called dataflow variables in the literature) are variables that can be written
only once; attempts to read the variable block until it has been written to.
<P/>
Synchronization variables are created with <Ref Func="CreateSyncVar"/>, written with <Ref Func="SyncWrite"/> and read
with <Ref Func="SyncRead"/>.

<Example><![CDATA[
gap> sv := CreateSyncVar();;
gap> RunAsyncTask(function()
>      Sleep(10);
>      SyncWrite(sv, MakeImmutable([1, 2, 3]));
>    end);;
gap> SyncRead(sv);
[ 1, 2, 3 ]
]]></Example>

<ManSection>
    <Func Name="CreateSyncVar"
      Arg=''/>

<Description>
The function <Ref Func="CreateSyncVar"/> takes no arguments. It returns a new synchronization variable. There is no need to
deallocate it; the garbage collector will free the memory and all related resources when it is no longer accessible.
</Description>
</ManSection>

<ManSection>
    <Func Name="SyncWrite"
      Arg='syncvar, obj'/>

<Description>
<Ref Func="SyncWrite"/> attempts to assign the value <A>obj</A> to <A>syncvar</A>. If <A>syncvar</A> has been previously
assigned a value, the call will fail with a runtime error; otherwise, <A>obj</A> will be assigned to <A>syncvar</A>.
<P/>
In order to make sure that the recipient can read the result, the <A>obj</A> argument should not be a thread-local
object; it should be public, read-only, or shared.
</Description>
</ManSection>

<ManSection>
    <Func Name="SyncRead"
      Arg='syncvar'/>

<Description>
<Ref Func="SyncRead"/> reads the value previously assigned to <A>syncvar</A> with <Ref Func="SyncWrite"/>. If no value has been
assigned yet, it blocks. It returns the assigned value.
</Description>
</ManSection>
  </Section>
</Chapter>

quality98%

¤ Dauer der Verarbeitung: 0.23 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.