德尔福基础

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并行

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Using\_TParallel.For\_from\_the\_Parallel\_Programming\_Library

# Using TParallel.For from the Parallel Programming Library #

*Go Up to [Using the Parallel Programming Library][]*

The **[Parallel Programming Library (PPL)][Using the Parallel Programming Library]** includes a loop function, [TParallel.For][], that allows to run its loops in parallel.

Within parallel loops, you must transform your operations into thread-safe operations. You can use members of the [System.SyncObjs][] unit, such as [TInterlocked methods][].

## Converting a For Loop into a `TParallel.For` Loop ##

**Delphi:**

<table> 
 <tbody> 
 <tr> 
 <th>For Loop</th> 
 <th>TParallel.For Loop</th> 
 </tr> 
 <tr> 
 <td> 
 <div> 
 <pre>for I := 1 to 10 do begin // … end; </pre> 
 </div> </td> 
 <td> 
 <div> 
 <pre>TParallel.For(1, 10, procedure(I: Integer) begin // … end); </pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

**C++:**

If you are using a [Clang-enhanced C++ compiler][Clang-enhanced C_ compiler], you can use [lambda expressions][]:

You can alternatively use a [functor][], which works with [both previous-generation compilers and Clang-enhanced compilers][]:

<table> 
 <tbody> 
 <tr> 
 <th>For Loop</th> 
 <th>TParallel.For Loop</th> 
 </tr> 
 <tr> 
 <td> 
 <div> 
 <pre>for (int i = 1; i &lt;= 10; i++) { // (Loop logic) } </pre> 
 </div> </td> 
 <td> 
 <div> 
 <pre>class TMyFunctor : public TCppInterfacedObject&lt;TProc__1&lt;int&gt; &gt; { public: void __fastcall Invoke(int I) { // (Loop logic) } }; // … TParallel::For(1, 10, System::DelphiInterface&lt;TProc__1&lt;int&gt; &gt;(new TMyFunctor())); </pre> 
 </div> </td> 
 </tr> 
 </tbody> 
</table>

If the loop needs access to one or more variables from the context outside the callback function, you must use a functor as follows:

1.  Declare variables in the functor class to hold copies or references to the variables that you need.
2.  Declare a constructor of the functor class that accepts the copies or references to those variables as parameters and initializes the corresponding functor variables with their values.
3.  Pass those variables to the contructor when you instantiate the functor.
4.  In your logic, in `Invoke()`, you can access those functor variables.

For example:

class TMyFunctor : public TCppInterfacedObject<TProc__1<int> > { public: TMyFunctor(int a, TB *b) : a(a), b(b) {} void __fastcall Invoke(int I) { // (Loop logic) } int a; TB *b; }; // … TParallel::For(1, 10, System::DelphiInterface<TProc__1<int> >(new TMyFunctor(a, b)));

# 分类方法 #

TTest = class;
     
     // Declaring metaclass type
     TTestClass = class of TTest; TTest = class public // Class methods class function add(I, J: Integer): Integer; class function GetClsName: string; // Virtual class method class function GetClsNameVirt: string; virtual; // Class getter and setter class function GetCount: Integer; class procedure SetCount(I: Integer); // Virtual class getter and setter class function GetStrProp: string; virtual; class procedure SetStrProp(N: string); virtual; // Class static class function GetStaticCount: Integer; static; class procedure SetStaticCount(I: Integer); static; // Class properties property Count: Integer read GetCount write SetCount; // Non-virtual property StrProp: string read GetStrProp write SetStrProp; // Virtual g/setters end; // Function that takes a class reference function RegisterTestType(Cls: TTestClass): boolean;

# 基本句法元素（Delphi） #

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Fundamental_Syntactic_Elements_(Delphi)

# 程序和功能（德尔福） #

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Procedures\_and\_Functions\_(Delphi)

# 表达式（德尔福） #

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Expressions\_(Delphi)

# 编译器属性 volatile #

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Compiler\_Attributes\#Volatile

# System.TimeSpan.TTimeSpan #

http://docwiki.embarcadero.com/Libraries/Tokyo/en/System.TimeSpan.TTimeSpan

# 使用并行编程库 #

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Using\_the\_Parallel\_Programming\_Library

# 简单类型（Delphi） #

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Simple\_Types\_(Delphi)

转载于:https://www.cnblogs.com/marklove/p/9503194.html

[Using the Parallel Programming Library]: http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Using_the_Parallel_Programming_Library
[TParallel.For]: http://docwiki.embarcadero.com/Libraries/Tokyo/en/System.Threading.TParallel.For
[System.SyncObjs]: http://docwiki.embarcadero.com/Libraries/Tokyo/en/System.SyncObjs
[TInterlocked methods]: http://docwiki.embarcadero.com/Libraries/Tokyo/en/System.SyncObjs.TInterlocked_Methods
[Clang-enhanced C_ compiler]: http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Clang-enhanced_C%2B%2B_Compilers
[lambda expressions]: http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Lambda_Expressions
[functor]: http://docwiki.embarcadero.com/RADStudio/Tokyo/en/How_to_Handle_Delphi_Anonymous_Methods_in_C%2B%2B#Using_a_Functor_.28Function_Object.29
[both previous-generation compilers and Clang-enhanced compilers]: http://docwiki.embarcadero.com/RADStudio/Tokyo/en/C%2B%2B_Compilers