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Class core.thread.fiber.Fiber

This class provides a cooperative concurrency mechanism integrated with the threading and garbage collection functionality. Calling a fiber may be considered a blocking operation that returns when the fiber yields (via Fiber.yield()). Execution occurs within the context of the calling thread so synchronization is not necessary to guarantee memory visibility so long as the same thread calls the fiber each time. Please note that there is no requirement that a fiber be bound to one specific thread. Rather, fibers may be freely passed between threads so long as they are not currently executing. Like threads, a new fiber thread may be created using either derivation or composition, as in the following example.

class Fiber ;


this (fn, sz, guardPageSize) Initializes a fiber object which is associated with a static D function.
this (dg, sz, guardPageSize) Initializes a fiber object which is associated with a dynamic D function.


state[get] Fiber.StateGets the current state of this fiber.


call (rethrow) Transfers execution to this fiber object. The calling context will be suspended until the fiber calls Fiber.yield() or until it terminates via an unhandled exception.
getThis () Provides a reference to the calling fiber or null if no fiber is currently active.
reset () Resets this fiber so that it may be re-used, optionally with a new function/delegate. This routine should only be called for fibers that have terminated, as doing otherwise could result in scope-dependent functionality that is not executed. Stack-based classes, for example, may not be cleaned up properly if a fiber is reset before it has terminated.
yield () Forces a context switch to occur away from the calling fiber.
yieldAndThrow (t) Forces a context switch to occur away from the calling fiber and then throws obj in the calling fiber.
factory (classname) Create instance of class specified by the fully qualified name classname. The class must either have no constructors or have a default constructor.
opCmp (o) Compare with another Object obj.
opEquals (o) Test whether this is equal to o. The default implementation only compares by identity (using the is operator). Generally, overrides and overloads for opEquals should attempt to compare objects by their contents. A class will most likely want to add an overload that takes your specific type as the argument and does the content comparison. Then you can override this and forward it to your specific typed overload with a cast. Remember to check for null on the typed overload.
toHash () Compute hash function for Object.
toString () Convert Object to a human readable string.


Rethrow Flag to control rethrow behavior of call
State A fiber may occupy one of three states: HOLD, EXEC, and TERM.


Status registers are not saved by the current implementations. This means floating point exception status bits (overflow, divide by 0), rounding mode and similar stuff is set per-thread, not per Fiber!


On ARM FPU registers are not saved if druntime was compiled as ARM_SoftFloat. If such a build is used on a ARM_SoftFP system which actually has got a FPU and other libraries are using the FPU registers (other code is compiled as ARM_SoftFP) this can cause problems. Druntime must be compiled as ARM_SoftFP in this case.


int counter;

class DerivedFiber : Fiber
        super( &run );

private :
    void run()
        counter += 2;

void fiberFunc()
    counter += 4;
    counter += 8;

// create instances of each type
Fiber derived = new DerivedFiber();
Fiber composed = new Fiber( &fiberFunc );

writeln(counter); // 0;
writeln(counter); // 2;
writeln(counter); // 6

counter += 16;
writeln(counter); // 22;
writeln(counter); // 30

// since each fiber has run to completion, each should have state TERM
writeln(derived.state); // Fiber.State.TERM
writeln(composed.state); // Fiber.State.TERM


Sean Kelly, Walter Bright, Alex Rønne Petersen, Martin Nowak


Distributed under the Boost Software License 1.0. (See accompanying file LICENSE)