C / C++ / MFC Discussion Boards

WaitForSingleObject - Handle for ShellExecute()

ndalal29-Mar-04 4:38

29-Mar-04 4:38

Hi,

I'm having trouble using WaitForSingleObject for the handle used in ShellExecute(). The mutex returned always has 0xffffffff, i.e. WAIT_FAILED.
Why dont I receive any of these:
WAIT_OBJECT_O, WAIT_ABANDONED or WAIT_TIMEOUT.

It seems that the handle from ShellExecute cannot be used with WaitForSingleObject. If thats the case, then what should I use to wait for the ShellExecute process to complete?

Note: ShellExecute process executes a batch file which has several commands to run on command prompt. This proocess takes several seconds to complete, which could vary though.

Any help or comments are appreciated.
Thanks,
- Nirav

===========================================
x = ShellExecute(handl, "open", "foo.bat", NULL, NULL, SW_HIDE);
mutex = WaitForSingleObject(handl,INFINITE);
do {
mutex = WaitForSingleObject(handl,INFINITE);
} while(mutex == WAIT_OBJECT_0);
if(mutex != WAIT_OBJECT_0)
return E_FAIL;

BOOL status = ReleaseMutex(handl);
if (status == 0) {
DWORD LastErr = GetLastError();
}
===========================================

Re: WaitForSingleObject - Handle for ShellExecute()

basementman29-Mar-04 4:44

basementman

29-Mar-04 4:44

Your second wait is returning the INVALID_HANDLE. If you use the INFINITE flag, then the second wait is unnecessary and invalid.

onwards and upwards...

Re: WaitForSingleObject - Handle for ShellExecute()

ndalal29-Mar-04 4:50

ndalal

29-Mar-04 4:50

OK.

If I remove the first wait, it still returns the same mutex (0xffffffff) from the second wait.

Any clue?

Thanks again.

Re: WaitForSingleObject - Handle for ShellExecute()

David Crow29-Mar-04 5:07

David Crow

29-Mar-04 5:07

The first parameter to ShellExecute() and WaitForSingleObject() are not the same thing. The former is a window handle, while the latter is a handle to an object. What you want is something like:

PROCESS_INFORMATION pi = {0};
CreateProcess(..., &pi);
WaitForSingleObject(pi.hProcess, ...);

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: WaitForSingleObject - Handle for ShellExecute()

ndalal29-Mar-04 6:09

ndalal

29-Mar-04 6:09

I'm not sure if I can execute a batch file on command line using CreateProcess.
Note that the batch file include several different commands (compile and link) which needs to execute on the "same" command line window.

CreateProcess execute an application with one command only. I'm not sure if it can execute a batch file.

If I execute the following code, I get exception handling error on CreateProcess() line.

===============================================
PROCESS_INFORMATION pi;
if(CreateProcess("foo.bat", NULL, NULL, NULL, FALSE, CREATE_DEFAULT_ERROR_MODE, NULL, NULL, NULL, &pi) == FALSE) {
return S_FALSE;
}

do {
mutex = WaitForSingleObject(pi.hProcess,INFINITE);
} while(mutex == WAIT_OBJECT_0);

Re: WaitForSingleObject - Handle for ShellExecute()

David Crow29-Mar-04 6:20

David Crow

29-Mar-04 6:20

ndalal wrote:
I'm not sure if it can execute a batch file.

Yes, it can be used with .bat files.

I do not think NULL is a valid option for the ninth parameter.

The do/while loop seems unnecessary as WaitForSingleObject() will do its own waiting without using any processor time. As you have it written, WaitForSingleObject() will wait indefinitely for the object's state to become signaled, but will then loop infinitely as the state will remain signaled.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: WaitForSingleObject - Handle for ShellExecute()

Michael Dunn29-Mar-04 8:45

Michael Dunn

29-Mar-04 8:45

ShellExecute() doesn't return a process handle even though the return type is HINSTANCE. Use ShellExecuteEx() to get a handle that you can wait on.

--Mike--
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Printing in a dialog based application

Member 426420329-Mar-04 4:12

Member 4264203

29-Mar-04 4:12

I am using a dialog based application.
The application will generate a report after doing a lot of testing.
I want the report to be printed whenever the user presses one button from the dialog box.
Can anyone help me.

Joesam

Re: Printing in a dialog based application

Antti Keskinen29-Mar-04 4:38

Antti Keskinen

29-Mar-04 4:38

See this article[^] by Richard Stringer. Should have everything you ever need in printing from MFC programs.

-Antti Keskinen

----------------------------------------------
The definition of impossible is strictly dependant
on what we think is possible.

Re: Printing in a dialog based application

Roger Allen30-Mar-04 0:53

Roger Allen

30-Mar-04 0:53

This article of mine MFC CDialog print/preview extension[^] will do exactly what you need.

Roger Allen - Sonork 100.10016
Strong Sad:
Clever I am? Next to no one.
Undiscovered and soggy.
Look up. Look down. They're around.
Probably laughing. Still, bright, watery.
Listed among the top. Ten.
Nine. Late night. Early morn.
Early mourn. Now I sleep.

static array of base class pointers??

LudaLuda29-Mar-04 4:00

LudaLuda

29-Mar-04 4:00

Hey guys,

here is the problem:

I have to keep an static array of pointers of type base class , and I should be able to assign each of these pointers to any of the derived class..

here is the code...

class Base
{
public:
static Base* basePtr[10];
}

class derived1 : public Base
{ }

class derived2 : public Base
{}

now in my main.cpp I want to be able to create objects of derived1 or derived2 and assign the basePtr to point to them....

how do I do that???

.....
...
derived1 d1
Base::basePtr[1] = &d1 // I tried this approach, the problem is...does this mean I have to have 10 different classes of d1 or d2 and then assign each of their references to the basePtr ??? Is there way to do this dynamically so that I do some thing like the following

Base::basePtr[1] = new derived1;

Pls help..

thanks

Re: static array of base class pointers??

ohadp29-Mar-04 4:37

ohadp

29-Mar-04 4:37

Without arguing about the design of these classes, grin, you can do:

<br />
for (int i=0; i<5; i++)<br />
{<br />
   Base::basePtr[i] = new derived1;<br />
   Base::basePtr[5+i] = new derived2;<br />
}<br />

what could be nicer would be to have the constructor of Base store the pointers itself.

<br />
Base::Base()<br />
{<br />
   basePtr[numObjects++] = this;<br />
}<br />

You would have to add a static 'numObjects' counter for this to work, or...

<br />
Base::Base(int pos)<br />
{<br />
   basePtr[pos] = this;<br />
}<br />

As long as you don't create 'Base' objects but only derived objects, you can just go and do this :

<br />
for (int i=0; i<5; i++)<br />
{<br />
   new derived1;<br />
   new derived2;<br />
<br />

OR:

<br />
   new derived1[i];<br />
   ned derived2[5+i];<br />
}<br />

Re: static array of base class pointers??

LudaLuda29-Mar-04 4:53

LudaLuda

29-Mar-04 4:53

oh one important detail I left out is that

my base class is abstract ....

so there will be instantiation of this class inside the main program.

I tried ur method above to have new objects created dynamically and store thier pointer to the array pointer but it doenst seem to be working

I tried

Base::basePtr[1] = new derived1;

this would not work ! I get a link , unresolved external for static Base::basePtr ...etc etc..

do I have to initialize the abstract class that contains the static array somewhere in the main code ??? how do I do that? or is it even possible?

Thanks

Re: static array of base class pointers??

ohadp29-Mar-04 4:57

ohadp

29-Mar-04 4:57

This happens because you don't declare the array itself.

You 'declared' it in the array, but that was only a 'state of purpose', you need to decalre the variable itself.

so, take your .cpp file, and somewhere in the begining write :

Base* Base::basePtr[10];

then it will link.

p.s. - if your base-class is abstract, then it will never be instantiated 'by itself'.

Add protocol programatically

Reza Shademani29-Mar-04 3:42

Reza Shademani

29-Mar-04 3:42

hi gang

is there anyone tried to add protocol such as netbuei to available installed protocol in win 2k ?
if yes ,give me a clue .
thnx in advance .

PNP_INFO again

Member 67007929-Mar-04 3:33

Member 670079

29-Mar-04 3:33

Hello again !
I post this message again for adding more detailes for my problem.
It seems that I've been missunderstood! I want to query directly the device.
The two methods that you recomended are for reading from registry. This information are available only if a driver is already installed. I want to comunicate to he device even if I don't have a driver instaled.
Thank you again

///////////////////////////////////////
// this is the original message posted
////////////////////////////////////
Hello !
My name is Cristi and I have a big big problem.
I want to get the plug and play informations from a printer connected via parallel port (or usb). Using DeviceIoControl with IOCTL__PAR_QUERY_DEVICE_ID is great in Windows 2000 or XP, but on Windows 95,98 and Me it doesn't work at all. I tried defining myself this IOCTLs with CTL_CODE macro but in vain.
I need to query directly the device and not the driver.
Please, if anyone knows, tell me how can I obtain the plug and play information on an operating system like Windows 95, 98 or ME

You can write me at funnycreeps@go.ro

Thank you !

expert advice needed (query results)

BlackDice29-Mar-04 3:22

BlackDice

29-Mar-04 3:22

I have an application that allows the user to make their own query by selecting fields and then viewing the results. As anyone who's seen my frustrated questions lately would know I've made a DLL to export these results to a .DBF file (the query is done on a MySQL database). This is my question: Should I actually export what they see in their results, or should I export the newest results? The dilemma occurs because the user may make a query with 100 records returned. However this being a large system, if they keep that screen up for a few seconds, something different might be input into the system which might make their query now return 101 records. Either way is easy to implement, I'm just looking for advice on which strategy I should use. Any help is greatly appreciated. Thanks! Poke tongue | ;-P

If it's broken, I probably did it

bdiamond

Re: expert advice needed (query results)

David Crow29-Mar-04 4:29

David Crow

29-Mar-04 4:29

bdiamond wrote:
Should I actually export what they see in their results, or should I export the newest results?

You could always make it an option. If the user is satisfied with the results that were returned, they might not want to bother with a requery.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: expert advice needed (query results)

BlackDice29-Mar-04 5:04

BlackDice

29-Mar-04 5:04

I also thought about that and was wondering. thanks!

If it's broken, I probably did it

bdiamond

Re: expert advice needed (query results)

ohadp29-Mar-04 4:30

ohadp

29-Mar-04 4:30

Perhaps you can give more background on what exactly is going to be done with these results...

What you're describing is a classic question of :

Is the user suppose to get a snapshot, or is he suppose to be able to view up-to-date resutls all the time.

The first one makes it easy for you, get the results, save them to disk, and you're done.

It's hard for me to understnad how you want to achive 'always up-to-date' with saving data to a file anyways ?

cheers

Re: expert advice needed (query results)

basementman29-Mar-04 4:40

basementman

29-Mar-04 4:40

My $.02:
In this day of GUI/WYSIWYG, you should save what is displayed to the user. They have to be satisfied with the display in order to save it to disk, and should not be suprised when they open the DBF and see something different.

onwards and upwards...

Re: expert advice needed (query results)

BlackDice29-Mar-04 5:06

BlackDice

29-Mar-04 5:06

thanks!

If it's broken, I probably did it

bdiamond

[eVC] Internationalization and Multiple Language Support

GuilhemMtp29-Mar-04 2:51

GuilhemMtp

29-Mar-04 2:51

I have to develop an application which can be use in several langages.
I show this sample on the site http://www.codeproject.com/cpp/mult_lang_support.asp[^] but it is very hard to convert this exemple for eVC.

Is there someone who can help me please.

Thank you

Sorry for my poor English Wink | ;)

Re: [eVC] Internationalization and Multiple Language Support

ohadp29-Mar-04 4:27

ohadp

29-Mar-04 4:27

Why not use the baisc support VC has for this ?
Which is declaring all your strings as resources, each with it's different language-ID, and then compiling the application (or resource-dll) with the specific language-flag ?

Re: [eVC] Internationalization and Multiple Language Support

Anonymous30-Mar-04 7:50

Anonymous

30-Mar-04 7:50

Thanks for your reaply
I don't understand own to use it.
My soft have to be internationalised.
I heard about dll, but I don't understand how to use whem.

Thank you for your help.

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