C / C++ / MFC Discussion Boards

Re: Memory leak when return char* from DLL

Rolf Kristensen31-Mar-09 23:04

31-Mar-09 23:04

Just follow what Dominik Reichl said in the first comment about ensuring that memory allocated in the DLL is released by the DLL again. Return the char-pointer to the DLL and let the DLL release it again.

Re: Memory leak when return char* from DLL

Shivanand Gupta1-Apr-09 0:18

Shivanand Gupta

1-Apr-09 0:18

return data char* is locally defined in DLL.
so how can release memory of that variable after returning
char* variable

Re: Memory leak when return char* from DLL

Rolf Kristensen1-Apr-09 0:39

Rolf Kristensen

1-Apr-09 0:39

When returning the char* then you take a copy of the char*, but they both point to the same memory in the heap of the DLL.

Just pass the copy of the char* from the application to the DLL again, and let the DLL release the memory in its heap.

You might consider returning a CString instead of a char*, and ensure that when the CString moves from DLL boundary to the Application boundary that a copy is made of the CString.

Re: Memory leak when return char* from DLL

Shivanand Gupta1-Apr-09 20:38

Shivanand Gupta

1-Apr-09 20:38

I have try but it is not working.
return char* is defined in dll's function as a local variable.
it will work well when we defined static variable. but i don't want
to create static variable in my DLL.

Re: Memory leak when return char* from DLL

Rolf Kristensen31-Mar-09 22:59

Rolf Kristensen

31-Mar-09 22:59

Thank you for confirming this. I'm in a situation myself where I'm considering to convert static-libraries into DLL's to improve linker times. The entire application is already using runtime library as DLL, so the conversion should be a matter of exporting all needed classes in the static libraries.

win32 Database

Paulraj G30-Mar-09 21:40

Paulraj G

30-Mar-09 21:40

Hi...

i am creating a application in win32. i need to access the sql or MSAccess databse. but i don't know how to connect win32 application with sql or MSAccess database. please can any one help me?

thanking you

G.Paulraj

Re: win32 Database

Stuart Dootson30-Mar-09 22:05

Stuart Dootson

30-Mar-09 22:05

Are you using MFC? If so, then the MFC database connectivity classes[^] will be useful.

If you're not using MFC, then the ATL database classes[^] may be useful.

Other alternative technologies are ODBC[^], ADO[^] or DAO[^]. They'll all be painful (to some degree) to use with raw C++.

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

Re: win32 Database

_AnsHUMAN_ 30-Mar-09 22:07

_AnsHUMAN_

30-Mar-09 22:07

How about reading about these api's from MSDN SQLHandle,SQLAllocHandle, SQLSetEnvAttr, SQLAllocHandle, SQLConnect, SQLAllocHandle, SQLExecDirec.

You need to google first, if you have "It's urgent please" mentioned in your question.
Wink | ;-)

_AnShUmAn_

Re: win32 Database

Rajesh R Subramanian30-Mar-09 22:12

Rajesh R Subramanian

30-Mar-09 22:12

_AnsHUMAN_ wrote:
SQLHandle, SQLAllocHandle, SQLSetEnvAttr, SQLAllocHandle, SQLConnect, SQLAllocHandle, SQLExecDirec.

Apparently, you want him to read-up about SQLAllocHandle() thrice? Big Grin | :-D

It is a crappy thing, but it's life -^ Carlo Pallini

Re: win32 Database

Stuart Dootson30-Mar-09 22:22

Stuart Dootson

30-Mar-09 22:22

It's a very important function Poke tongue | ;-P

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

Re: win32 Database

Rajesh R Subramanian30-Mar-09 22:26

Rajesh R Subramanian

30-Mar-09 22:26

Makes perfect sense.

It is a crappy thing, but it's life -^ Carlo Pallini

Re: win32 Database

_AnsHUMAN_ 31-Mar-09 1:31

_AnsHUMAN_

31-Mar-09 1:31

I wanted him to read this function more than once. So after reading each API go back and read about SQLAllocHandle... Probably the OP may understand it's importance. Smile | :)

Just a typo, copy pasted the API name thrice

On another note, there's no harm in reading an API three times or more or until the point when it starts making some sense. $Shucks | :-\$

You need to google first, if you have "It's urgent please" mentioned in your question.
Wink | ;-)

_AnShUmAn_

to read chm file using vc++

vidyajagadish30-Mar-09 21:02

vidyajagadish

30-Mar-09 21:02

hi i need the vc++ code that as to read chm file format.
thanks in advance

Re: to read chm file using vc++

Rajesh R Subramanian30-Mar-09 21:25

Rajesh R Subramanian

30-Mar-09 21:25

I hope the HTML Help SDK[^] may be of help to you.

It is a crappy thing, but it's life -^ Carlo Pallini

VC++

p_196030-Mar-09 20:36

p_1960

30-Mar-09 20:36

Hi ,
Im new to VC++...May i know what"s the difference b/w MFC and vc++ and where to start with...

im planning to start with Programming windows with MFC (Jeff procise)..
Please correct me if im wrong...

Re: VC++

Rajesh R Subramanian30-Mar-09 20:43

Rajesh R Subramanian

30-Mar-09 20:43

Visual C++ may refer to the Microsoft C++ compiler, or even the IDE. You can think of it as C++ on windows. MFC is a c++ framework written around Windows APIs to make life easier. Wikipedia has separete entries for Visual C++[^] and MFC[^]. Give them a read.

p_1960 wrote:
im planning to start with Programming windows with MFC (Jeff ~~procise~~ Prosise)..

That would be a very good start if you are good at object oriented programming, specifically C++. (But legend says that you must start off with Win API and then move forward to MFC, not that it is a rule though)

Good luck with your learning. It must be fun. Smile | :)

It is a crappy thing, but it's life -^ Carlo Pallini

How to reduce .avi file size..

tns_ranjith30-Mar-09 20:31

tns_ranjith

30-Mar-09 20:31

When I Captured video from webcam up to 30 seconds ....avi file is taking upto 80 MB...How to reduce the size of .avi file in KB ..Plz Help me..

Re: How to reduce .avi file size..

Rajesh R Subramanian30-Mar-09 20:40

Rajesh R Subramanian

30-Mar-09 20:40

AVI compression looks like a viable option? There are video compression libraries on the internet (some with source code and samples).

It is a crappy thing, but it's life -^ Carlo Pallini

How to get ordinal value of function programitically ?

MANISH RASTOGI30-Mar-09 20:29

MANISH RASTOGI

30-Mar-09 20:29

Dear All,
I have created a dll in vc and exported some function. How can get ordinal value from function name in vc? I searched on google but could not find the result which I was looking for.

Thanks
Manish

can somebody help me to solve this problem? Pls help me, as soon as possible. This is a numerical method question.

Sunther30-Mar-09 20:02

Sunther

30-Mar-09 20:02

solve the following system:

2x1-x2=1
-xi+2xi+1=0, i=1,2,.....,n-2.
-xn-1+2xn=1.

Using a)thomas method,
b) Jacobi method,
c) SOR scheme (use w=1 (Gauss-Seidel), w=1.1, w=1.2, w=1.3, w=1.4, w=1.5).

Use intial approximation x^(0) e=10^-6. Limit the maximum number of iteration to N=500. Display the output in the following form:

Number of iteration for convergence:?

Solution:
x1=

x2=

.

x20=

Re: can somebody help me to solve this problem? Pls help me, as soon as possible. This is a numerical method question.

Stuart Dootson30-Mar-09 20:20

Stuart Dootson

30-Mar-09 20:20

I'm not doing your assignment for you - but Google[^] can help you find pages like this[^].

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

Re: can somebody help me to solve this problem? Pls help me, as soon as possible. This is a numerical method question.

Rajesh R Subramanian30-Mar-09 20:30

Rajesh R Subramanian

30-Mar-09 20:30

See points 2, 3 and 9 in this post[^]

Re: can somebody help me to solve this problem? Pls help me, as soon as possible. This is a numerical method question.

Member 43208446-Nov-11 22:09

Member 4320844

6-Nov-11 22:09

Hi

If this is your problem:

   2x1-x2=1     ...................[1]
-xi+2xi+1=0, i=1,2,.....,n-2. .....[2]
-xn-1+2xn=1  ......................[3]

solution:

from [1] you get:

x(2)= 2*x(1)-1
from [3] you get:

x(n-1) = 2*x(n) -1

from [2] you get:

 n= ? : rem n value should be set

 for j=1 to 50
 rem  50 is max iterations set to.

 for i=1 to n-2
  if i=2 then
   x(2)= 2*x(1)-1
  end if

  x(i)= 2*x(i+1)

 next i
  x(n-1) = 2*x(n) -1
next j

Remark: I hope I understood your problem, since the solution
correctness depends on that too.
If your your problem is not stated correctly, that
belongs to you.
I hope that I helped, if you need more let me know.

system() parameter complications

gamefreak229130-Mar-09 19:49

gamefreak2291

30-Mar-09 19:49

Alright, I'm trying to have my program, which was writting in C++ using Dev-Cpp 4.9.9.2, open a separate program.
I know this can be achieved throw the use of system() but I can't seem to get it to work right, I'm currently using the command line:

system("c:\\Program Files\\Internet Explorer\\iexplorer.exe");

I get the error "'c:\Program' is not recognized as an internal or external command, operable program or batch file."

Re: system() parameter complications

Stuart Dootson30-Mar-09 20:18

Stuart Dootson

30-Mar-09 20:18

It's just a command line, as passed to CMD, so put double quotes around the path as it contains spaces:
```
system("\"c:\\Program Files\\Internet Explorer\\iexplorer.exe\"");
```
Isn't it iexplore.exe, not iexplorer.exe?

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

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