C / C++ / MFC Discussion Boards

Dave Bryant29-Sep-03 11:33

29-Sep-03 11:33

Assuming pBuff is a pointer to an array of bytes, this won't work because sizeof(pBuff) will always return 4 (the size of the pointer). You need to pass in the actual number of bytes to copy instead.

Dave
http://www.cloudsofheaven.org

Re: Should be easy...

RobJones29-Sep-03 11:55

RobJones

29-Sep-03 11:55

That was it, thanks..

Rob

Whoever said nothing's impossible never tried slamming a revolving door!

GetModuleFileName instance and registering app

Raymond So29-Sep-03 9:15

Raymond So

29-Sep-03 9:15

I'm trying to place a value in HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run so that my app starts up when windows starts up, as a background app. I've implemented DLLRegisterServer so that it is invoked when the setup.exe runs (I've set the .exe to self-register under InstallShield). In DLLSelfRegister, I need the path to the .exe so that the value in the registry is set properly and the .exe runs from that path. I use GetModuleFileName to get the path of the app, but when regsvr32 myApp.exe is run, the app is not instantiated yet.

I used MFC to create a dialog based app
Here's a code snipet:

CSysTrayDemoApp theApp; //MFC generated

...

//Implement this funciton so that regsvr32 can invoke it to register exe.
STDAPI DllRegisterServer()
{
char path[MAX_PATH];

DWORD pathLen = sizeof(fileName);

__asm int 3;

GetModuleFileName(theApp.m_hInstance, path, pathLen);
...

theApp.m_hInstance is not instantiated and thus I can't get the path name.

Does anyone have experience in registering an app/is there a better way of doing this?

Thanks,
Raymond

Re: GetModuleFileName instance and registering app

Dave Bryant29-Sep-03 10:59

Dave Bryant

29-Sep-03 10:59

Try passing in NULL as the HINSTANCE for GetModuleFileName() - that means it retrieves the name of the current module. The most likely reason for theApp.m_hInstance not being initialised is that DllRegisterServer normally does not need to call DllMain(), so your normal application initialisation has not occurred.

Dave
http://www.cloudsofheaven.org

Re: GetModuleFileName instance and registering app

igor196029-Sep-03 12:58

igor1960

29-Sep-03 12:58

As you are registering EXE -- this is outproc server.
Why would you need regsvr32 for that (it's used for inproc servers)?
Instead, you should start your outproc server with /REGSERVER and process it properly in yours InitInstance (or whatever)...

"...Ability to type is not enough to become a Programmer. Unless you type in VB. But then again you have to type really fast..."
Me

Re: GetModuleFileName instance and registering app

Michael Dunn29-Sep-03 16:26

Michael Dunn

29-Sep-03 16:26

EXEs aren't registered with DllRegisterServer() (as the name says, "DLL"). You should instead register in response to being run with /RegServer.

--Mike--
Ericahist | Homepage | RightClick-Encrypt | 1ClickPicGrabber
CP SearchBar v2.0.2 released

Taskbar window button

blade29-Sep-03 9:01

blade

29-Sep-03 9:01

Is there a way to trap a mouse click on your taskbar window button.

My application does not have the title bar. So am facing two problems.

1. I cannot restore my application by clicking on the taskbar window button, if it is minimized.

2. On Windows 2000 if I choose Minimize All, my app is not minimized along with the other apps.

Help wanted badly!!!

Thanks,
Blade

Executing an EXE from memory

Larry Antram29-Sep-03 8:54

Larry Antram

29-Sep-03 8:54

I would like to execute an EXE from memory (instead of disk). Is this practical? If so, does anyone have any hints or suggestions as to how it can be accomplished?

Re: Executing an EXE from memory

David Crow29-Sep-03 11:14

David Crow

29-Sep-03 11:14

Yes. Search MSDN and the Net for the PE file format.

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: Executing an EXE from memory

Larry Antram29-Sep-03 12:23

Larry Antram

29-Sep-03 12:23

I undoubtably have horrible MSDN searching skills, however the most I gleaned from a massive article with way too much information I'm not interested in was:

"When PE files are loaded into memory via the Windows loader"... bla bla bla.

I'm just wondering if there is some relatively easy way (in the Win32/C++ world) to launch a PE from memory (instead of disk)?

From disk we have lots of API's... WinExec, CreateProcess, ShellExecute, etc.

What's the basic technique for launching from memory? Is assembly required? Confused | :confused:

I'm just basically looking for a tidbit of information to give me a headstart -- before having to comprehend all of the information about PE files and apparently the Windows loader and such.

Re: Executing an EXE from memory

Michael Dunn29-Sep-03 16:29

Michael Dunn

29-Sep-03 16:29

Larry Antram wrote:
I would like to execute an EXE from memory

No, because the PE loader uses memory-mapped files to move the EXE image into memory. This requires that the EXE be a real file on disk.

--Mike--
Ericahist | Homepage | RightClick-Encrypt | 1ClickPicGrabber
CP SearchBar v2.0.2 released

How to create an "Open With" list?

ralfoide29-Sep-03 8:45

ralfoide

29-Sep-03 8:45

Hi!

I need to be able to launch a viewer for a given file from my application (Win32/MFC/C++). Ideally I'd like to present the user with choices similar to the "Open With..." feature of the explorer shell.

I tried SHGetFileInfo but it keeps returning 0 for the flag SHGFI_TYPENAME (failure).

So I assume there's two part in my quest:
1- Find the type (mime type?) a given extension (I don't necessarily have the file created yet -- i.e. I'd like the user to be able to choose before creating the file)
2- Find a list of suitable applications (path, "user friendly" name) that can open that mime type.

I seems like I could just go and fish the info from the registry, but would that work on any windows version?

Regards
R/

Re: How to create an "Open With" list?

Amit Dey29-Sep-03 13:33

Amit Dey

29-Sep-03 13:33

ralfoide wrote:
I could just go and fish the info from the registry
seems like the only way. Blush | :O

Hush,hush...
thought I heard you call my name now.

Kula Shaker.

Amit Dey
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Easy question about formatting a string

NewHSKid29-Sep-03 8:18

NewHSKid

29-Sep-03 8:18

Hi everyone,

Just a quick question. Is there a way to display binary when formatting a string? I know %d is decimal, %X is hex....is there one that even exists for binary?

Jimmy

Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

Re: Easy question about formatting a string

Ravi Bhavnani29-Sep-03 8:35

Ravi Bhavnani

29-Sep-03 8:35

There isn't a ready-made format specifier like %b that will format an integer in binary. You'll have to brew your own by walking the bits.

/ravi

Let's put "civil" back in "civilization"
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Re: Easy question about formatting a string

David Crow29-Sep-03 8:38

David Crow

29-Sep-03 8:38

NewHSKid wrote:
...is there one that even exists for binary?

No, you'll need to roll your own.

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: Easy question about formatting a string

WREY29-Sep-03 11:49

WREY

29-Sep-03 11:49

There are several ways. Here are a few.

The example below will display the binary representation for the decimal 100. In addition to '#including' <bitset>, you'll also have to '#include' <limits>

cout<<"\n 100: " <<bitset<numeric_limits<unsigned int>::digits>(100)<<endl;

the="" example="" below="" will="" also="" display="" the="" binary="" configuration="" for="" decimal="" 85.

cout<<"\n="" 85:="" "="" <<bitset<8="">::bitset(85) <<endl;

there are="" some="" subtle="" differences="" between="" the="" first="" example="" and="" second,="" but="" biggest="" is="" that="" in="" second="" you="" interested="" only="" having="" eight="" bits="" to="" represent="" value,="" whereas="" you'll="" get="" 32="" value.="" iow,="" can="" restrict="" number="" of="" want="" have="" representing="" value="" you're="" displaying.

here's="" one="" for="" letters.="" it="" will="" show="" binary="" representation="" letter="" 'a'="" using="" 8="" bits.

cout<<"\n="" \"a\":="" "="" <<bitset<8="">('A') <<endl;

lastly, here's="" one="" to="" show="" a="" string="" of="" letters="" (e.g.="" "abcd").

bitset<32=""> Ltrs = bitset<numeric_limits<unsigned int>::digits>('ABCD');
cout<<"\n \"ABCD\": " <

Valid Pointer ??

Shah Shehpori29-Sep-03 8:10

Shah Shehpori

29-Sep-03 8:10

Hi!

How can i determine that the pointer is pointing to a valid memory address??

e.g:

consider

class CTest
{
 public:
  
   void Release()
   {
     delete this;
   }
};

CTest *pTest = NULL

pTest = new CTest();

pTest->Release();

If you look at the last statement i.e pTest->Release();, the memory poionted by pTest is deleted, but pTest still contains some value. I want to determine whether the value in pTest is a valid address or not ? How can i do so ?

N.B, I've read somewhere that in MFC the is a function something like AfxIsValidAddress(), but i would prefer a non-mfc solution

Re: Valid Pointer ??

Ravi Bhavnani29-Sep-03 8:39

Ravi Bhavnani

29-Sep-03 8:39

You can use one of several Win32 APIs to check the validity of a pointer: IsBadCodePtr(), IsBadReadPtr(), IsBadStringPtr() and IsBadWritePtr() as well as the Huge analogs.

/ravi

Let's put "civil" back in "civilization"
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Re: Valid Pointer ??

David Crow29-Sep-03 8:53

David Crow

29-Sep-03 8:53

Unfortunately, AfxIsValidAddress() and related functions like IsBadReadPtr() don't tell you if the pointer has been freed or not. They know if the address can be read from and/or written to. You'll just need to get into the habit of assigning NULL to the pointer after delete has been called.

Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

Re: Valid Pointer ??

igor196029-Sep-03 13:06

igor1960

29-Sep-03 13:06

class CTest<br />
{ <br />
public:  <br />
   	CTest** m_ptr;<br />
	CTest(CTest** ptr = NULL)<br />
	{<br />
	 	m_ptr = ptr;<br />
	}<br />
	~CTest();<br />
	{<br />
           if(m_ptr)<br />
		*m_ptr = NULL;<br />
	}<br />
	void Release()   <br />
	{     <br />
		delete this;   <br />
	}<br />
};<br />
<br />
<br />
CTest *pTest = NULL<br />
pTest = new CTest(&pTest);<br />
pTest->Release();

"...Ability to type is not enough to become a Programmer. Unless you type in VB. But then again you have to type really fast..."
Me

Re: Valid Pointer ??

Michael Dunn29-Sep-03 16:33

Michael Dunn

29-Sep-03 16:33

Shah Shehpori wrote:
How can i determine that the pointer is pointing to a valid memory address??

There is a big difference between "valid memory" and "memory that contains valid data". Unfortunately the computer can only tell you about the former. Even after you delete a pointer, the memory is not usually removed from your app's process space, so you could go on dereferencing the pointer and not cause a GPF.
As someone else said, get in the habit of setting pointers to NULL after a delete or Release() call and you'll avoid such bugs.

--Mike--
Ericahist | Homepage | RightClick-Encrypt | 1ClickPicGrabber
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Visual Assebmler

Stefak29-Sep-03 7:17

Stefak

29-Sep-03 7:17

Please help me to find some Assembler IDE which work on Win32.
(Kind of VASM).
I spend much time for surfing all over WWW but links I found was broken Cry | :((

Code Red

DirectShow with MFC

juryu29-Sep-03 7:09

juryu

29-Sep-03 7:09

Hi guys,

I am just starting to use DirectShow. I've managed to make it play a video in a CStatic in my dialog box. But now I want to draw something else there, like, put something on top of the video that is playing. I've tried using the device context from the CStatic but that doesn't seem to work - I guess I "gave" it to DirectShow and don't have control over it anymore. Another possibility would be to put another CStatic in front of the video playing, but that doesn't seem to work either, the video just plays over everything! Any suggestions?

Re: DirectShow with MFC

Ravi Bhavnani29-Sep-03 8:42

Ravi Bhavnani

29-Sep-03 8:42

See Stephane's articles Video overlay using Microsoft DirectShow[^] and Video overlay part II - An introduction to hypervideo[^].

/ravi

Let's put "civil" back in "civilization"
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