Re: memcpy related - C / C++ / MFC Discussion Boards

Re: garbage value problem????

amitmistry_petlad 8-Mar-07 2:39

amitmistry_petlad

8-Mar-07 2:39

yes ,i have do it. I had compare when got NULL then return s="".

Re: garbage value problem????

prasad_som8-Mar-07 2:51

prasad_som

8-Mar-07 2:51

Then, its definitely due to code, you have not shown here. Can you explain, how you are using this function, and where you are facing problem.

Prasad
Notifier using ATL | Operator new[],delete[][^]

Re: garbage value problem????

krmed8-Mar-07 2:58

krmed

8-Mar-07 2:58

I think you also have a problem here:

size_t len = wcslen(source) * sizeof(LPCWSTR);	//len=0

wcslen(source) should give you the length you need - but then you are multiplying it by sizeof(LPCWSTR) which is 4 bytes since it's a pointer. That really isn't necessary.

You should then be able to wrap the rest in an if:

if (len > 0)
{
    char* tempOutFile= new char[len];//tempOutFile=Garbage valve need tempOutFile =""
    WideCharToMultiByte(CP_ACP,0,source,-1,tempOutFile,(int)len,NULL,NULL);
    string s = tempOutFile;
    if(tempOutFile)
    {
        delete[] tempOutFile;
    }
    return s;
}

Hope that helps.

Karl - WK5M
PP-ASEL-IA (N43CS)
PGP Key: 0xDB02E193
PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193

memcpy related

NiceNaidu8-Mar-07 0:37

NiceNaidu

8-Mar-07 0:37

Hi friends,
What is the Max limit of the number of bytes copied from Source to Destination in mempcy ??

Thanks in advance.

Appu..
"My blood group is not B+.But I have it my blood"

Re: memcpy related

Vinod Sankaranarayanan8-Mar-07 1:30

Vinod Sankaranarayanan

8-Mar-07 1:30

Hi,

The maximum limit is mostly compiler dependent.

It will be the maimum size of "size_t" .

i.e : "size_t" is an alias of "unsigned long" , so the maximum size of "unsigned long" is ULONG_MAX

Note : ULONG_MAX is 4294967295

Regards,

vinsankar

Re: memcpy related

toxcct8-Mar-07 1:40

toxcct

8-Mar-07 1:40

Vinod A Sankaranarayanan wrote:
It will be the maimum size of "size_t" .

that's right

Vinod A Sankaranarayanan wrote:
i.e : "size_t" is an alias of "unsigned long"

wrong here. unsigned long is always 4 bytes, even on 64 bits systems; size_t is 8 bytes on 64 bits systems

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Re: memcpy related

Nemanja Trifunovic8-Mar-07 2:00

Nemanja Trifunovic

8-Mar-07 2:00

toxcct wrote:
unsigned long is always 4 bytes, even on 64 bits systems;

Actually, unsigned long is 8 bytes on most 64-bit Unix systems; the Standard does not specify the size of unsigned long

Programming Blog
utf8-cpp

Re: memcpy related

toxcct8-Mar-07 2:12

toxcct

8-Mar-07 2:12

Nemanja Trifunovic wrote:
the Standard does not specify the size of unsigned long

doesn't it ?

AFAIK, only [signed | unsigned] ints weren't specified...

short and long still length to 2 and 4 bytes respectively

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Re: memcpy related

Nemanja Trifunovic8-Mar-07 2:58

Nemanja Trifunovic

8-Mar-07 2:58

toxcct wrote:
doesn't it ?

Nope[^], it pretty much guarantees only minimal sizes for integer types. As I said, on most 64-bit Unix systems, long is 64 bits.

Programming Blog
utf8-cpp

Re: memcpy related

PJ Arends8-Mar-07 5:00

PJ Arends

8-Mar-07 5:00

I always thought it was that way too Confused | :confused:

Either I was always wrong or the C standard has been changed since I first learned this.

You may be right
I may be crazy
-- Billy Joel --

Within you lies the power for good, use it!!!

Re: memcpy related

toxcct8-Mar-07 5:45

toxcct

8-Mar-07 5:45

the game seems to be over for us... let's go back to school ! lol

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Re: memcpy related

prasad_som8-Mar-07 1:34

prasad_som

8-Mar-07 1:34

Maximum size_t can hold.

Prasad
Notifier using ATL | Operator new[],delete[][^]

Re: memcpy related

NiceNaidu8-Mar-07 2:21

NiceNaidu

8-Mar-07 2:21

Thanks everyone..

Appu..
"My blood group is not B+.But I have it my blood"

WaitForMultipleObjects

Shaileshhex8-Mar-07 0:35

Shaileshhex

8-Mar-07 0:35

I have a call to WaitForMultipleObjects() which waits for any of 4 events to happen ...but the statements after the call to WaitForMultipleObjects() are not executed.

i am not able to debug and get wat value is returned by the call WaitForMultipleObjects()

thanks in advance

Re: WaitForMultipleObjects

Roger Stoltz8-Mar-07 2:03

Roger Stoltz

8-Mar-07 2:03

What does your code look like?
Post the call to WaitForMultipleObjects() and its surroundings and please use <pre> / </pre> tags when posting code.

Are you absolutely sure that WaitForMultipleObjects() is called? Place a breakpoint on it to verify this.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

Re: WaitForMultipleObjects

Mark Salsbery8-Mar-07 6:34

Mark Salsbery

8-Mar-07 6:34

Shaileshhex wrote:
but the statements after the call to WaitForMultipleObjects() are not executed.

Even if you use a timeout value? If you never get past a wait function then none of the objects
were signalled.

Mark

"Great job, team. Head back to base for debriefing and cocktails."
(Spottswoode "Team America")

Re: WaitForMultipleObjects

Shaileshhex8-Mar-07 19:51

Shaileshhex

8-Mar-07 19:51

hi...
Thanks for ur replies...
i think ur right may b the event is not signalled.... code is as below
aslso its not my code and, event created is ITC_APP_EVENT_RIGHTSCAN...i have no idea where ITC_APP_EVENT_RIGHTSCAN comes from.....

hCenterDelta=CreateEvent(NULL, FALSE, FALSE, _T("ITC_APP_EVENT_CENTERSCAN"));
hCenterState=CreateEvent(NULL, TRUE, FALSE, _T("ITC_APP_STATE_CENTERSCAN"));

hRightDelta=CreateEvent(NULL, FALSE, FALSE,_T("ITC_APP_EVENT_RIGHTSCAN"));
hRightState=CreateEvent(NULL, TRUE, FALSE, _T("ITC_APP_STATE_RIGHTSCAN"));

hLeftDelta=CreateEvent(NULL, FALSE, FALSE, _T("ITC_APP_EVENT_LEFTSCAN"));
hLeftState=CreateEvent(NULL, TRUE, FALSE, _T("ITC_APP_STATE_LEFTSCAN"));

hIRDAReset=CreateEvent(NULL, TRUE, FALSE, _T("NOTIFICATION_EVENT_WAKEUP"));

h = CreateEvent( NULL, TRUE, FALSE, EVENTNAME_KEYBOARD_CHANGE );

if ( h != INVALID_HANDLE_VALUE ) {
SetEvent( h );
CloseHandle( h );
} // end if
//the closed event
hClosed = CreateEvent(NULL,TRUE,FALSE,_T("RfidCloseEvent"));
HANDLE hObjectList[] =
{
hClosed,
hCenterDelta,
hRightDelta,
hLeftDelta,
hIRDAReset
};

while (1)
{
DWORD wc = WaitForMultipleObjects(
sizeof(hObjectList)/sizeof(HANDLE), // number of handles in array
hObjectList, // object-handle array
FALSE, // wait option
(DWORD) INFINITE // time-out interval
);
//THE breakpoint holds at this point...
switch ( wc)
{
WAIT_OBJECT_0 + 2: //Center button
if (WaitForSingleObject(hRightState,0)==WAIT_OBJECT_0)
{
//some code
}
etc..etc..
}

}

LET ME KNOW UR THOUGHTS

bye

Re: WaitForMultipleObjects

Mark Salsbery8-Mar-07 20:06

Mark Salsbery

8-Mar-07 20:06

The only thing I see in your code sample is

WAIT_OBJECT_0 + 2: //Center button

WAIT_OBJECT_0 + 2 corresponds to the hRightDelta event handle, not the hCenterDelta event handle.
Remember the array is indexed from 0 Smile | :)

If you put a breakpoint on the switch ( wc) line and execution never pauses there then none of the
five events eing waited on are getting signalled.

Mark

"Great job, team. Head back to base for debriefing and cocktails."
(Spottswoode "Team America")

Re: WaitForMultipleObjects

Shaileshhex9-Mar-07 0:57

Shaileshhex

9-Mar-07 0:57

hi Mark...
I found that the events ITC_APP_EVENT_RIGHTSCAN etc ..were not present in the devices registry...so i added these events ..but still that event does not get signalled ....

my device uses WIN CE 3.0...but the event gets signalled for another device which has WINCE 4.2

does this mean that 3.0 does not recognise ITC_APP_EVENT_RIGHTSCAN??...if so then how do i find which is the correct event

thanks

Re: WaitForMultipleObjects

Mark Salsbery9-Mar-07 6:18

Mark Salsbery

9-Mar-07 6:18

Hmm I have no idea how event objects relate to the registry.

You are creating named event objects in your code. That means if an event with the same name
already exists on the system then you'll get a handle to that same event. If the event does not
already exist in the system, you get a new event object.

Are you sure these "ITC_APP_EVENT_xxx" strings represent the name of named events in another
process? This has nothing to do with the registry.

Mark

"Great job, team. Head back to base for debriefing and cocktails."
(Spottswoode "Team America")

distinguish a DVD-RAM from a flash memory card!

reza matinnejad8-Mar-07 0:04

reza matinnejad

8-Mar-07 0:04

How could i distinguish a DVD-RAM from a flash memory card
(both are Removable storage drives)
in runtime?

Re: distinguish a DVD-RAM from a flash memory card!

PS@Codeproj8-Mar-07 2:10

PS@Codeproj

8-Mar-07 2:10

I hope "GetDriveType" API will return
DRIVE_RAMDISK for DVD-RAM Disk and
DRIVE_REMOVABLE for Removeable Drive.

Thanks & Rgds,
Sri..

doubt in textbox controls used in MFC

harshadha7-Mar-07 23:50

harshadha

7-Mar-07 23:50

Hai,

Good Evening....

I was working with the controls of textbox i have a doubt in that can anyone
clear it....

I created a form in MFC by having various controls.
1.In that i have a textbox in which iam entering some values.
2.I want that value to be printed in the message box...
Can anyone please tell me how to do....

Thanks
Harshadha

Re: doubt in textbox controls used in MFC

Hamid_RT7-Mar-07 23:58

Hamid_RT

7-Mar-07 23:58

You have a editbox CEdit m_EDit; and it has values "12345" now you want to show these values use of m_Edit1.GetWindowText();

WhiteSky

Re: doubt in textbox controls used in MFC

harshadha8-Mar-07 0:02

harshadha

8-Mar-07 0:02

hai,

i cant understand ..
Iam passing values to the editbox in run time ,then if i click a command button iam displaying a messagebox,where i want these value to be shown...

Harshadha

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