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version 2.109.0

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Function std.concurrency.spawn

Starts fn(args) in a new logical thread.

Tid spawn(F, T...) (
  F fn,
  T args
)
if (isSpawnable!(F, T));

Executes the supplied function in a new logical thread represented by Tid. The calling thread is designated as the owner of the new thread. When the owner thread terminates an OwnerTerminated message will be sent to the new thread, causing an OwnerTerminated exception to be thrown on receive().

Parameters

NameDescription
fn The function to execute.
args Arguments to the function.

Returns

A Tid representing the new logical thread.

Notes

args must not have unshared aliasing. In other words, all arguments to fn must either be shared or immutable or have no pointer indirection. This is necessary for enforcing isolation among threads.

Similarly, if fn is a delegate, it must not have unshared aliases, meaning fn must be either shared or immutable.

Example

static void f(string msg)
{
    writeln(msg); // "Hello World"
}

auto tid = spawn(&f, "Hello World");

Example

Fails

char[] has mutable aliasing. 

string msg = "Hello, World!";

static void f1(string msg) {}
static assert(!__traits(compiles, spawn(&f1, msg.dup)));
static assert( __traits(compiles, spawn(&f1, msg.idup)));

static void f2(char[] msg) {}
static assert(!__traits(compiles, spawn(&f2, msg.dup)));
static assert(!__traits(compiles, spawn(&f2, msg.idup)));

Example

New thread with anonymous function 

spawn({
    ownerTid.send("This is so great!");
});
writeln(receiveOnly!string); // "This is so great!"

Authors

Sean Kelly, Alex Rønne Petersen, Martin Nowak

License

Boost License 1.0.