Solved

Freeing Char Array memory

Posted on 2004-09-20
6
235 Views
Last Modified: 2010-04-01
I have the following code:

char *bodybuf=0; unsigned int bodysize=0;
IStream *istream;
hr = imsg->OpenProperty(PR_BODY, &IID_IStream, STGM_READ, 0, (IUnknown**)&istream);
if (hr==S_OK)
{
                  STATSTG stg = {0};
                  hr = istream->Stat(&stg,STATFLAG_NONAME);
                            if (hr==S_OK)
                              {
                        bodysize = stg.cbSize.LowPart; // won't bother checking for >2gb messages!
                        bodybuf = new char[bodysize+1];
                        ULONG red;
                        hr = istream->Read(bodybuf, bodysize, &red);
                        if (hr!=S_OK)
                                  bodysize=0;
                        else if (red<bodysize)
                                  bodysize=red;
                                  bodybuf[bodysize]=0;
                        }
                        istream->Release();
                  }

in the event that the amount red from the IStream (red) is less than the amount allocated (bodysize + 1), the string will be null terminated by the call to bodysize = red; and then bodybuf[bodysize] = 0;  

however, when I call delete [] bodybuf, will this leak memory?  If so, what is the proper way to handle this?
0
Comment
Question by:jjacksn
  • 3
  • 2
6 Comments
 
LVL 55

Accepted Solution

by:
Jaime Olivares earned 300 total points
ID: 12107399
delete operator will not evaluate the lenght of your string, or where is a terminating null character located, it will free the same memory amount as allocated in new char[bodysize+1], so don't worry about this.
0
 
LVL 10

Assisted Solution

by:Sys_Prog
Sys_Prog earned 200 total points
ID: 12107662
Though there wont be any problem deleting, as jaime said, delete just deletes the memory allocated by new

It does not look out for lengt og string or NULL charater etc etc

Hwever, why dont u allocate only that much memory as needed

THus, after u come to know that I need red aamount of mmoery, allocate that much.......that wuld not waste your memory

Amit
0
 
LVL 55

Expert Comment

by:Jaime Olivares
ID: 12107760
Since IStream don't has a method to know how many bytes are pending, I think jjacksn implementation is ok. There is no (little) memory waste because once processed, buffer will be deleted.
0
Best Practices: Disaster Recovery Testing

Besides backup, any IT division should have a disaster recovery plan. You will find a few tips below relating to the development of such a plan and to what issues one should pay special attention in the course of backup planning.

 
LVL 10

Expert Comment

by:Sys_Prog
ID: 12107824
I think once its kknow that REad has succeded, then red wuld contain the size. Hence that can be used to allocaate

amit
0
 
LVL 5

Author Comment

by:jjacksn
ID: 12108792
but the read needs the allocated buffer.
0
 
LVL 10

Expert Comment

by:Sys_Prog
ID: 12110940
ohh...yes....i am sorry...didnt notice that
0

Featured Post

ScreenConnect 6.0 Free Trial

Discover new time-saving features in one game-changing release, ScreenConnect 6.0, based on partner feedback. New features include a redesigned UI, app configurations and chat acknowledgement to improve customer engagement!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction This article is the first in a series of articles about the C/C++ Visual Studio Express debugger.  It provides a quick start guide in using the debugger. Part 2 focuses on additional topics in breakpoints.  Lastly, Part 3 focuses on th…
This article will show you some of the more useful Standard Template Library (STL) algorithms through the use of working examples.  You will learn about how these algorithms fit into the STL architecture, how they work with STL containers, and why t…
The viewer will learn how to use the return statement in functions in C++. The video will also teach the user how to pass data to a function and have the function return data back for further processing.
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.

803 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question