Functional/parallel-Phpdoc专题

The parallel\Runtime API provides a great degree of control to the power PHP programmer, and those intimately familiar with writing applications that use parallel concurrency.

The functional API provides less control in exchange for the ability to make decisions for the programmer:

• all executing runtimes are bootstrapped identically

• scheduling is determined by the API, not the programmer

parallel\run provides the guarantee that the task will begin to execute in parallel as soon as allowed by hardware and operating system constraints, without needlessly creating runtimes. For most applications the functional API should be preferred.

parallel\bootstrap

Bootstrapping

说明

void <span class="methodname">parallel\bootstrap ( <span class="methodparam">string $file )

Shall use the provided file to bootstrap all runtimes created for automatic scheduling via parallel\run.

Exceptions

Warning

Shall throw <span class="type">parallel\Runtime\Error\Bootstrap if previously called for this process.

Warning

Shall throw <span class="type">parallel\Runtime\Error\Bootstrap if called after parallel\run.

参见

parallel\run

Execution

说明

Future<span class="type">null <span class="methodname">parallel\run ( <span class="methodparam">Closure $task )

Shall schedule task for execution in parallel.

Future<span class="type">null <span class="methodname">parallel\run ( <span class="methodparam">Closure $task , array $argv )

Shall schedule task for execution in parallel, passing argv at execution time.

Automatic Scheduling

If a \parallel\Runtime internally created and cached by a previous call to <span class="function">parallel\run is idle, it will be used to execute the task. If no <span class="classname">\parallel\Runtime is idle parallel will create and cache a \parallel\Runtime.

Note:

\parallel\Runtime objects created by the programmer are not used for automatic scheduling.

参数

task
A Closure with specific characteristics.

argv
An array of arguments with specific characteristics to be passed to task at execution time.

Task Characteristics

Closures scheduled for parallel execution must not:

• accept or return by reference
• accept or return internal objects (see notes)
• execute a limited set of instructions

Instructions prohibited in Closures intended for parallel execution are:

• yield
• use by-reference
• declare class
• declare named function

Note:

Nested closures may yield or use by-reference, but must not contain class or named function declarations.

Note:

No instructions are prohibited in the files which the task may include.

Arguments Characteristics

Arguments must not:

• contain references
• contain resources
• contain internal objects (see notes)

Note:

In the case of file stream resources, the resource will be cast to the file descriptor and passed as int where possible, this is unsupported on Windows.

Internal Objects Notes

Internal objects generally use a custom structure which cannot be copied by value safely, PHP currently lacks the mechanics to do this (without serialization) and so only objects that do not use a custom structure may be shared.

Some internal objects do not use a custom structure, for example <span class="classname">parallel\Events\Event and so may be shared.

Closures are a special kind of internal object and support being copied by value, and so may be shared.

Channels are central to writing parallel code and support concurrent access and execution by necessity, and so may be shared.

Warning

A user class that extends an internal class may use a custom structure as defined by the internal class, in which case they cannot be copied by value safely, and so may not be shared.

返回值

Warning

The return parallel\Future must not be ignored when the task contains a return or throw statement.

Exceptions

Warning

Shall throw parallel\Runtime\Error\Closed if parallel\Runtime was closed.

Warning

Shall throw <span class="type">parallel\Runtime\Error\IllegalFunction if task is a closure created from an internal function.

Warning

Shall throw <span class="type">parallel\Runtime\Error\IllegalInstruction if task contains illegal instructions.

Warning

Shall throw <span class="type">parallel\Runtime\Error\IllegalParameter if task accepts or argv contains illegal variables.

Warning

Shall throw <span class="type">parallel\Runtime\Error\IllegalReturn if task returns illegally.

参见

目录

• parallel\bootstrap — Bootstrapping
• parallel\run — Execution