How to use Process Class in Managed C++

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Introduction

The simplest definition of Process is executing instance of an application. The process contains at least one thread. The thread is a fundamental unit of the operating system. Windows is a multitasking operating system. Every process contains at least one thread. Windows NT family system and Windows 95/98 based system support preemptive multitasking. So, we can work freely for multiple threads and multiple processors.

Process Class

In Microsoft .NET framework all the namespaces derived from Object. The System.Diagnostics namespace provides the information about the process state, start the new process, etc. In this namespace allows to starts the new process, kill process, etc.

In process class allows to monitor local system process information or remote system process information. We also interact with the ProcessThread and ProcessModule classes. The ProcessStartup class provides the arguments passing and etc. ProcessStartInfo Constructor use to initializes the process information.

ProcessStartInfo contains the following properties.

Arguments

The arguments property use to set the argument in file name like ShellExecute function.

Filename

The FileName Property is used to set the application name . We can set this property before starting the process class.

UseShellExecute

If we set this is True we can perform the file operations (like, printing the contents in that file). If we set False we just execute the application.

WindowStyle

We set and get the WindowStyle in process starting time.

WaitForExit

WaitForExit property is to wait for the process fora specified time.

For Example :-

Notepad->waitForExit(1000) // waits 1000 seconds.

Kill

Kill property is to kill the currently running process.

Ex :-  notePad->Kill();

The following code is to start the notepad. It waits 1000 secounds and kills it automatically using kill property in Process class.

// Create Process

Process *notePad = new Process();

// set the filename
notePad->StartInfo->FileName   = "notepad.exe";

// Arguments
notePad->StartInfo->Arguments = "textfile.txt";

//Start the process
notePad->Start();

// Wait for 1000 secounds
notepad->waitForExit(1000);

//Kill the process
notepad->Kill();

Process Thread Class

The Process Thread contains information about the currently running process. We control the threads within the process. We set or get the thread proprieties like low, high. The Process Thread class contains the following properties.

BasePriority

The BasePrority is used to get the priority.

CurrentPriority

The CurrentPriority Class is to get the current priority

PriorityLevel

The PriorityLevel is to Get or set the priority level

ThreadState

The ThreadState is to get the current state

ProcessModule class

The ProcessModule class is to get the information about the process module. In ProcessModule class, properties are used to get the information like get module name, memory size in the module, etc.

The following code explains the use of ProcessModule class to get module name, fileinfo etc.

// Create process
Process *notePad = new Process();

// set filename
notePad->StartInfo->FileName   = "notepad.exe";

//Arguments
notePad->StartInfo->Arguments = "selvam.txt";

//Start
notePad->Start();

//Sleep
System::Threading::Thread::Sleep(1000);

//Create processmodule class
ProcessModule *myProcessModule;
myProcessModule = notePad->MainModule;

String *strFileName, *strModuleName;
int nMemory;

//Get the process file name, Module name etc..
strFileName = myProcessModule->FileName;
strModuleName = myProcessModule->ModuleName;
nMemory = myProcessModule->ModuleMemorySize;

Conclusion

The .NET framework is used to simplify the programming model. So, we can easily interact with the operating system. The Process class is useful to start the new process, stop the existing process and control the process. ProcessModule class is used to get the module information in the running application.