Re: TerminateProcess() - C / C++ / MFC Discussion Boards

Joe Woodbury31-Mar-09 13:04

31-Mar-09 13:04

Why not have the first program start the second using CreateProcess() and then wait on the process handle?

An alternative is to use a globally named event and have the first application wait on it (which is pretty much what my first suggestion is doing.)

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: TerminateProcess()

gamefreak229131-Mar-09 13:12

gamefreak2291

31-Mar-09 13:12

Because I'm attending a High School that offers no programming class at all and thus I have no prior instructed knowledge and have no idea how to do that. I've attempted via examples from searching around but I couldn't get them to work because I just don't have enough knowledge at this point.

Re: TerminateProcess()

Joe Woodbury31-Mar-09 13:38

Joe Woodbury

31-Mar-09 13:38

DWORD ExecuteProcess(LPCTSTR pCommandLine, LPCTSTR pDirectory = NULL, DWORD millisecondsTimeout = INFINITE)
{
	// _alloca allocates the memory on the stack, so I don't need to worry about cleaning it up
	// You could use new and then delete the buffer later
	TCHAR* pCmdLine = (TCHAR*) _alloca((lstrlen(pCommandLine) + 1) * sizeof(TCHAR));
	lstrcpy(pCmdLine, pCommandLine);

	STARTUPINFO startupInfo;
	memset(&startupInfo, 0, sizeof(startupInfo));
	startupInfo.cb = sizeof(startupInfo);

	PROCESS_INFORMATION processInfo;
	memset(&processInfo, 0, sizeof(processInfo));

	DWORD rval;

	if (CreateProcess(NULL, pCmdLine, NULL, NULL, FALSE, CREATE_DEFAULT_ERROR_MODE, NULL, pDirectory, &startupInfo, &processInfo))
	{
		rval = WaitForSingleObject(processInfo.hProcess, millisecondsTimeout);
	}
	else
	{
		rval = GetLastError();
	}

	CloseHandle(processInfo.hProcess);
	CloseHandle(processInfo.hThread);

	return rval;
}

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: TerminateProcess()

gamefreak229131-Mar-09 20:14

gamefreak2291

31-Mar-09 20:14

okay, thanks for the tidbit of code but I still dont know where to insert it or how to tell it what to open

Re: TerminateProcess()

Iain Clarke, Warrior Programmer31-Mar-09 22:50

Iain Clarke, Warrior Programmer

31-Mar-09 22:50

You call this function in the first program instead of the system function.
It runs the second program (given in one of the parameters), waits for the second program to finish, then the function returns, so you can carry on doing whatever the first program should do.

Iain.

In the process of moving to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), give me a job!

Re: TerminateProcess()

Joe Woodbury1-Apr-09 5:28

Joe Woodbury

1-Apr-09 5:28

You call ExecuteProcess with the same command line you would use at a command prompt. The directory is what the current directory should be set to.

For example, ExecuteProcess(_T("C:\\Windows\\System32\\Notepad.exe win.ini"), _T("C:\\Windows"));

This is very simple code, but it illustrates the basic principles. Go to MSDN and read up on CreateProcess() and WaitForSingleObject(). Read up on multi-threading and synchronization. Experiment. Step through the code. Until you fully understand this code, you will not be qualified to write any code.

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: TerminateProcess()

gamefreak229131-Mar-09 20:20

gamefreak2291

31-Mar-09 20:20

I never did get an answer to my initial question

Re: TerminateProcess()

Stuart Dootson31-Mar-09 20:29

Stuart Dootson

31-Mar-09 20:29

You can't do what you want. system doesn't give you back the identity of your process, so you have no way to (later) control it. You have to use some other mechanism to create the process, like (as Joe suggested) CreateProcess, which does give you the process identity (through the PID and a process handle in the case of CreateProcess).

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: TerminateProcess()

Iain Clarke, Warrior Programmer31-Mar-09 22:58

Iain Clarke, Warrior Programmer

31-Mar-09 22:58

gamefreak2291 wrote:
I never did get an answer to my initial question

Your original question was posted when Europe had just gone to bed, India was debating getting to eat its breakfast Bhaji, and the Americas were having their after work beer. Or in your case, doing their homework.

1/ You don't pay us - we'll answer if / when we feel like.
2/ I'll give you credit for not putting "URGENTZ" in your subject line!

Anyway, Joe has given you a very good answer - if you need details, functions like CreateProcess have very long documentation to read.

I wish you success with your course,

Iain.

In the process of moving to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), give me a job!

tapi

Member 47646831-Mar-09 8:38

Member 476468

31-Mar-09 8:38

I am upgrading from an older version of Visual Studio to Visual Studio Express 9.0. In my code I have #include tapi.h. This causes an error. Does anyone know how to solve this?

Re: tapi

Joe Woodbury31-Mar-09 9:47

Joe Woodbury

31-Mar-09 9:47

It's in the platform SDK.

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: tapi

Member 4764681-Apr-09 6:45

Member 476468

1-Apr-09 6:45

Windows SDK will not load with Visual Studio 2008. In the Platform SDK the dialer example uses tapi.h and does not comiple with VS2008. Do you have the dialer example from the Windows SDK?

Re: tapi

Joe Woodbury1-Apr-09 8:38

Joe Woodbury

1-Apr-09 8:38

Member 476468 wrote:
Windows SDK will not load with Visual Studio 2008

That makes no sense. Windows SDK doesn't "load" it simply is. Since the latest Windows SDK included the Visual Studio 2008 compiler, I'm pretty damn sure it works with Visual Studio 2008.

Did you download this:

http://www.microsoft.com/downloads/details.aspx?familyid=E6E1C3DF-A74F-4207-8586-711EBE331CDC&displaylang=en[^]

And search because IT'S THERE!

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: tapi

Member 4764682-Apr-09 4:45

Member 476468

2-Apr-09 4:45

If you only have the Visual Studio 2008 EXPRESS, the Windows SDK will not download into your PC.

I was able to solve the problem with '#include tapi.h'. When I created the project, Visual Studio left the "Preprocessor Definitions" blank. When I put in "WIN32;_DEBUG;_WINDOWS" it compiled OK.

Thanks for the responses.

Re: tapi

David Crow1-Apr-09 3:31

David Crow

1-Apr-09 3:31

Member 476468 wrote:
Does anyone know how to solve this?

Solve what? Confused | :confused:

"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

Re: tapi

Member 4764681-Apr-09 6:47

Member 476468

1-Apr-09 6:47

In Visual Studio 2008, what replaces tapi.h?

Re: tapi

David Crow1-Apr-09 7:15

David Crow

1-Apr-09 7:15

Have you looked in the two include folders to see if the file exists, or search the .h files to see if they contain TAPI-related functions?

Multiple Inheritance question

ForNow31-Mar-09 6:41

ForNow

31-Mar-09 6:41

Hi,

I have derived class which has 2 base calsses CSyncObject and CSingleLock

Since the input to the CSingeLock is a pointer to a CSyncObject my question is

if I first create the CSyncObject can I reference that object object when executing

the Constructer for the CSingleLock with the "this" pointer

e.g. class mylock() : public CSyncObject(NULL) , public CSingeLock(this->

my question really is am I going down the right path

I would assume the "this" pointer gets initialized after excuting the first

contructer

Re: Multiple Inheritance question

Stuart Dootson31-Mar-09 7:10

Stuart Dootson

31-Mar-09 7:10

ForNow wrote:
I would assume the "this" pointer gets initialized after excuting the first contructer

No, you should be OK - this code does 'the right thing':

#include <iostream>

class A
{
public:
   A(int x) { x_ = x; }
   int x_;
};

class B
{
public:
   B(A* a) { std::cout << a->x_ << std::endl; }
};

class C : public A, public B
{
public:
	C(int y) : A(y), B(static_cast<A*>(this)) {}
};

int main(int, char**)
{
   C c(33);
}

VC++ (unlike gcc) does raise a warning[^] about doing this, but reading the warning description, I don't think it applies in this case.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: Multiple Inheritance question

ForNow31-Mar-09 16:24

ForNow

31-Mar-09 16:24

It worked

Please explain what is the value of "this" pointer on entrance to B from my undertanding static_cast<a*> is just a cast

????

Re: Multiple Inheritance question

Stuart Dootson31-Mar-09 20:23

Stuart Dootson

31-Mar-09 20:23

ForNow wrote:
from my undertanding static_cast<a*> is just a cast

Not in the presence of multiple inheritance - with multiple inheritance, you have two bases whose members you have to contain in your object. That means that for (say) class C : public class A, public class B, you have this layout in memory:

+---------------+
|   A members   |
+---------------+
|   B members   |
+---------------+
|   C members   |
+---------------+

So, to cast a C* to a B*, you will have an offset, equal to the size of A's members.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: Multiple Inheritance question code worked

ForNow31-Mar-09 18:11

ForNow

31-Mar-09 18:11

Hi,

class mylock : public CSyncObject, public CSingleLock
{
public:
mylock(BOOL bInitialLock);
BOOL Unlock();
};

mylock :: mylock(BOOL bInitialLock) : CSyncObject(NULL), CSingleLock(static_cast<CSyncObject*>(this), bInitialLock)

{
bInitialLock = FALSE;
}

Made a breakpoint when I tried to instatiate mylock with following code mylock my_threadlock(init_s);

at mylock the this value was 1feb8 as I steped into CsyncObject it remained 1feb8 when I got to CsingleLock's

contructer this value was bumped to 1FEC0 However m_hObject value was 1FEB8 CsyncObject value

Still have some debugging to do but thankx

this article also elucidates the point you tried to make

http://carcino.gen.nz/tech/cpp/multiple_inheritance_this.php

thankx again

Re: Multiple Inheritance question

Joe Woodbury31-Mar-09 8:11

Joe Woodbury

31-Mar-09 8:11

I disagree with Stuart. The "this" pointer should rarely be used in an initializer list. This is especially apt here since CSyncObject has virtual classes and the virtual table hasn't been set up at this point.

I also think your class is a mistake and misunderstands CSyncObject() and CSingleLock(). The point is that there is one synchronization object with multiple threads locking that object. That locking is done by instantiated CSingleLock() at the start of a scope and upon exit of that scope, CSingleLock will be destructed regardless regardless of how the scope was exited.

Moreover, with your code, what does CSyncObject even represent?

Finally, note that CSyncObject will be destructed before CSingleLock which will attempt to unlock the destructed CSyncObject.

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: Multiple Inheritance question

Stuart Dootson31-Mar-09 12:22

Stuart Dootson

31-Mar-09 12:22

Joe Woodbury wrote:
The "this" pointer should rarely be used in an initializer list.

It all depends whether he actually uses what the this pointer points at in the constructor or just stores it for later use. Storing for later use? Yeah, you'll be OK.

Joe Woodbury wrote:
...the virtual table hasn't been set up at this point.

The vtable will be consistent with the definition of the base class in the base class constructor (see this Scott Meyers article[^] for confirmation).

However, you do need to be very careful and aware of what's happening...which is why I probably shouldn't have said the OP would be OK with using this.

Joe Woodbury wrote:
I also think your class is a mistake and misunderstands CSyncObject() and CSingleLock(). The point is that there is one synchronization object with multiple threads locking that object. That locking is done by instantiated CSingleLock() at the start of a scope and upon exit of that scope, CSingleLock will be destructed regardless regardless of how the scope was exited.

Yeah, I wasn't even looking that far Blush | :O

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: Multiple Inheritance question

ForNow31-Mar-09 15:32

ForNow

31-Mar-09 15:32

As Far CsingLeObject Being Distructed I can always Create on the Heap as it will exist for the Life time of the app

Since threads are always Coming and going it may not be a bad idea to have to around

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