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i am using this function to get device lists.
void CDeviceList::GetDeviceList(std::vector<string> &info)
{
int i = 0;
HRESULT hr;
CComPtr<ICreateDevEnum> pCreateDevEnum;
hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, (void**)&pCreateDevEnum);
if (hr != NOERROR)
{
return;
}
CComPtr<IEnumMoniker> pEm;
hr = pCreateDevEnum->CreateClassEnumerator( CLSID_VideoInputDeviceCategory, &pEm, 0);
if (hr != NOERROR)
{
return;
}
pEm->Reset();
ULONG cFetched;
IMoniker *pM;
char* name = new char[255];
char* loc = NULL;
while(hr = pEm->Next(1, &pM, &cFetched), hr==S_OK)
{
IPropertyBag *pBag;
hr = pM->BindToStorage(0,0,IID_IPropertyBag,(void**)&pBag);
if(SUCCEEDED(hr))
{
VARIANT var;
var.vt = VT_BSTR;
hr = pBag->Read(L"FriendlyName", &var, NULL);
wcstombs(name, var.bstrVal, 255);
if (hr == NOERROR)
{
loc = strstr(name,"(VFW)");
if (loc==NULL)
{
info.push_back(name);
}
}
SAFE_RELEASE(pBag);
}
SAFE_RELEASE(pM);
}
delete[] name;
}
I have written a class cDeviceHandler. I want when i start thread it should compare two device lists and display message. code of cDeviceHandler class is given below:
#include "StdAfx.h"
#include "DeviceHandler.h"
CDeviceHandler::CDeviceHandler(void)
{
dList.GetDeviceList(devList);
}
void CDeviceHandler::start(void)
{
startThread = TRUE;
CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)ThreadProc, this, 0, NULL);
}
void CDeviceHandler::stop(void)
{
startThread = FALSE;
}
int CDeviceHandler::ThreadProc(LPVOID lpParam)
{
CDeviceHandler* ptr = (CDeviceHandler*) lpParam;
while(ptr->startThread)
{
vector<string> nList;
ptr->dList.GetDeviceList(nList);
char * cDeviceName = new char[260];
int status = ptr->CompareLists(ptr->devList,nList,cDeviceName);
switch(status)
{
case 0: {
TRACE("No Device Arrived nor Removed\n");
}
break;
case 1: {
TRACE("Device Removed \"%s\"\n",cDeviceName);
}
break;
case 2: {
TRACE("Device Arrived \"%s\"\n",cDeviceName);
}
break;
}
delete[] cDeviceName;
ptr->devList = nList;
Sleep(500);
}
return 0;
}
whenever i try to get new device list using
ptr->dList.GetDeviceList(nList);
previous device list is discarded and all member variables of current object are reset. Why is this happening?? can anyone explain it to me?
Regards,
K. Masood
modified on Tuesday, October 13, 2009 12:03 AM
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Use the code block button to the purpose.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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tibbasultanpur wrote:
whenever i try to get new device list using
ptr->dList.GetDeviceList(nList);
previous device list is discarded and all member variables of current object are reset.
Is this happening via your code? If so, just set a breakpoint on the "discard and reset" code. Learn to use the debugger. It'll quickly help to narrow the problem to just a handful of lines.
"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
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Thanks.
When this code line executes current object is reset.
ptr->dList.GetDeviceList(nList);
and when i go into this function, on this code line object is reset.
hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, (void**)&pCreateDevEnum);
hr returns S_OK, whole functions executes successfully and i get new list in nList (string vector).
I could not understand why is this happening.
How can i solve this problem?
I want whenever a new device is arrived or removed, a member function of this class (CDeviceHandler) is called.
or is there any other way to do this, please guide me.
Regards
K. Masood
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tibbasultanpur wrote: I want whenever a new device is arrived or removed...
Do you need to respond to the WM_DEVICECHANGE message?
"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
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Hello all,
I have a function like this
void fn_VersionInfo(const char** EngineVersionInfo)
{
}
I have to initialize a string into "EnginneVersionInfo" variable of function parameter. Can any body help me.
Thanks to all
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Well, look at the parameters.
You pass it a pointer to a pointer to a bunch of chars.
In C/C++, the most basic string is a pointer to a bunch of chars, usually NULL terminated.
So, we can say that fn_VersionInfo takes a pointer to a string. So you pass a pointer to a string.
That could either be a string you create yourself, or one that function creates for you. I suspect the latter, but you'll have to read the documentation to discover that.
Where is this function from? Does it have any documentation? Can you read the source?
If you let it create a string, who is responsible for deleting it afterwards?
Answering that last question will answer your original question.
*Not* looking for the answer to my last question means you will at best get bad habits, at worst will make your software crash when two parts of it try and tidy up the same variable twice.
Iain.
ps, I appear to be dishing out lessons in paranoid programming today. Like there's any other kind...
I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need contract work done, give me a job! http://cv.imcsoft.co.uk/[ ^]
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Hello Iain,
Thanks for replying.
Actually this have a documentation. I have to write the body of this function. This function exists in a DLL. I don't have to think outside code of the DLL. Sombody just call my function.
Pls reply
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Shaheen.India wrote: void fn_VersionInfo(const char** EngineVersionInfo)
{
}
void fn_VersionInfo(const char** EngineVersionInfo)
{
*EngineVersionInfo = "00.00.00.00";
}
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Hello CPallini
Thanks it works fine
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It is a good idea to pass in a second size_t parameter which specifies the size of the memory allocated for the string. Otherwise it could lead to a buffer overrun.
And if you want to use real C++ style do this -
void fn_VersionInfo(const char*& EngineVersionInfo, size_t size)
{
strcpy_s(EngineVersionInfo, size, "version string");
}
«_Superman_»
I love work. It gives me something to do between weekends.
Microsoft MVP (Visual C++)
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Hello!
Could anyone, please, forward me the right direction to do HEX->BIN->DEC conversions with 40 bit variable.
The point:
I have a CEdit type input on a dialog and a CComboBox to select data type. The user can choose to input data in HEX, DEC, BIN, formats the data length can be up to 40 bits (I use a char[5] type variable to store data in BIN). I have already made functions for getting user input from HEX and BIN (below):
<br />
void FillBuffer(void)<br />
{<br />
CString str;<br />
<br />
char Bit = 0;<br />
char Byte = 0;<br />
char Mask = 0;<br />
char Buf = '0';<br />
<br />
<br />
m_CardNumber.GetWindowTextA(str);<br />
str.MakeUpper();<br />
<br />
for(int i = 0;i<sizeof(Card.Data);i++)<br />
{<br />
Card.Data[i] = 0x00;
}<br />
<br />
int MaxLength;<br />
<br />
switch(PrevFormat)<br />
{<br />
case HEX:
{<br />
MaxLength = 10;<br />
<br />
if(str.GetLength() < 10)<br />
MaxLength = str.GetLength();<br />
<br />
for(int i = 0;<MaxLength;i++)<br />
{<br />
switch(str.GetAt(i))<br />
{<br />
case '0':<br />
Mask = 0;<br />
break;<br />
case '1':<br />
Mask = 1;<br />
break;<br />
case '2':<br />
Mask = 2;<br />
break;<br />
case '3':<br />
Mask = 3;<br />
break;<br />
case '4':<br />
Mask = 4;<br />
break;<br />
case '5':<br />
Mask = 5;<br />
break;<br />
case '6':<br />
Mask = 6;<br />
break;<br />
case '7':<br />
Mask = 7;<br />
break;<br />
case '8':<br />
Mask = 8;<br />
break;<br />
case '9':<br />
Mask = 9;<br />
break;<br />
case 'A':<br />
Mask = 10;<br />
break;<br />
case 'B':<br />
Mask = 11;<br />
break;<br />
case 'C':<br />
Mask = 12;<br />
break;<br />
case 'D':<br />
Mask = 13;<br />
break;<br />
case 'E':<br />
Mask = 14;<br />
break;<br />
case 'F':<br />
Mask = 15;<br />
break;<br />
};<br />
if(Bit%2 == 0 || Bit == 0)<br />
{<br />
Mask = Mask << 4;<br />
}<br />
<br />
Card.Data[Byte] = Card.Data[Byte]|Mask;<br />
<br />
Bit++;<br />
<br />
if(Bit%2 == 0)<br />
{<br />
Byte++;<br />
}<br />
<br />
<br />
}<br />
break;
}<br />
case BIN:
{<br />
MaxLength = 40;<br />
<br />
if(str.GetLength() < 40)<br />
MaxLength = str.GetLength();<br />
<br />
for(int i = 0;i<MaxLength;i++)<br />
{<br />
Buf = str.GetAt(i);<br />
Bit++;<br />
<br />
if(Buf == '1')<br />
{<br />
Mask = 1;<br />
Mask = Mask << ((Bit % 8 > 0) ? ( 8 - (Bit % 8) ) : 0);<br />
Card.Data[Byte] = Card.Data[Byte] | Mask;<br />
}<br />
<br />
if(Bit%8 == 0)<br />
{<br />
Byte++;<br />
}<br />
}<br />
break;
}<br />
case DEC:<br />
{<br />
<br />
<br />
break;
}<br />
default:<br />
break;<br />
<br />
};<br />
<br />
<br />
}<br />
<br />
All this works fine, but, how to handle Dec to bin in my case?
Thanks
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I would use strtol (well, its longer cousin...) for it all:
BOOL fillArray(LPCSTR s, int base, unsigned char data[5])
{
const unsigned __int64 GUARD = 1099511627776LL;
char * pcStop;
unsigned __int64 n = _strtoui64(s, &pcStop, base);
if ( n < GUARD )
{
unsigned char * p = (unsigned char *)(&n) + 4;
for (int i=0; i<5; i++)
{
data[i] = *p;
p--;
}
return TRUE;
}
else
return FALSE;
}
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Hi All,
I want to use PosstThreadMessage() function and i want to check if the thread handle is available before that, because sometimes the thread will be created and some times the the thread might not be created ...
So if the thread is not created i want the condition to fail ...
ex:
if( handle available)
{
ThreadPtr->PosstThreadMessage(MyMessage);
}
So can you tell me how to verify this .
Thanks..
Hari
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And what happens when the thread finishes between checking for calling the CheckThreadAvailability and PostThreadMessage functions?
By it's nature such a function would be useless.
I think you need to go back to your more basic design to address this issue, rather than papering over the cracks.
With multithreading, you have to imagine that you are on a multi code spiteful processor. Anything bad that could possibly happen, will.
Keep track of the thread handles. Even when a thread finishes, the handle is still valid - you need to close it with CloseHandle too. (I think MFC will do that for you, but I don't touch MFC threading with a bargepole. I use Win32 exclusively - better documented).
Iain.
I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need contract work done, give me a job! http://cv.imcsoft.co.uk/[ ^]
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You may use (with caveats suggested by the "Warrior Programmer") GetExitCodeThread function [^].
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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hi,
I have to convert pdf file to tif file using C .would anyone help me providing source code .regards
Bill
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No-one is going to give you a few lines of code to do this.
As you don't already realise this, you have a lot of learning / work ahead of you.
You need to find / pay for a pdf library that can render a PDF into a HDC.
Capture that HDC (which could be very large) into a bitmap.
Convert that bitmap into a tiff.
What about multipages? Maybe your pdf library can "print" one page at a time?
I hope that helps you with your google search terms. I know there are articles on CP for bitmap to tiff. And for simple PDF rendering.
Iain.
I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need contract work done, give me a job! http://cv.imcsoft.co.uk/[ ^]
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you can provide me code in c# also
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Do you understand "gimme codez" doesn't work here, don't you?
Anyway, you may try: "gimme codez urgentz plz plz" or "gimme codez ASAP".
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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billcodes wrote: you can provide me code in c# also
That's extremely kind of you. My answer before was not dependent on language.
Iain.
I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need contract work done, give me a job! http://cv.imcsoft.co.uk/[ ^]
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I can haz cheeseburger?
Visual Studio is an excellent GUIIDE.
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> As you don't already realise this, you have a lot of learning / work ahead of you.
>You need to find / pay for a pdf library that can render a PDF into a HDC.
Is it a joke ?
You should learn Win32 api, GDI+, and COM : ~25 lines of code...
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If you are going to sledge people, you might at least take the time and trouble to sledge the right person.
Henry Minute
Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”
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<br />
<br />
#include "stdafx.h"<br />
#include <iostream><br />
using namespace std;<br />
<br />
<br />
void copy_array(char from[], char to[])<br />
{<br />
int i = 0;<br />
while(from[i] != '\0')<br />
{<br />
to[i] = from[i];<br />
i++; <br />
}<br />
to[i] = '\0';<br />
}<br />
<br />
<br />
void copy_pointer(char *from, char *to)<br />
{<br />
while((*to++ = *from++) != '\0');<br />
}<br />
<br />
int _tmain(int argc, _TCHAR* argv[])<br />
{<br />
char *from = "c plus plus";<br />
char *to = "oooooooooooooooo";<br />
copy_pointer(from, to);
<br />
cout << to << endl;<br />
<br />
return 0;<br />
}<br />
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