std::launch (3) - Linux Manuals

std::launch: std::launch


std::launch - std::launch


Defined in header <future>
enum class launch : /* unspecified */ {
async = /* unspecified */,
deferred = /* unspecified */, (since C++11)
/* implementation-defined */

Specifies the launch policy for a task executed by the std::async function. std::launch is an enumeration used as BitmaskType.
The following constants denoting individual bits are defined by the standard library:

Constant Explanation
std::launch::async a new thread is launched to execute the task asynchronously
std::launch::deferred the task is executed on the calling thread the first time its result is requested (lazy evaluation)

In addition, implementations are allowed to:

* define additional bits and bitmasks to specify restrictions on task interactions applicable to a subset of launch policies, and
* enable those additional bitmasks for the first (default) overload of std::async.

See also

async runs a function asynchronously (potentially in a new thread) and returns a std::future that will hold the result
        (function template)