Solved

Memory Leak? C++ unmanaged. Simple code.

Posted on 2013-12-27
1
377 Views
Last Modified: 2013-12-28
Not familiar with unmanaged C++. Wondering if this following simple code is acceptable, or does it contain a memory leak. When does tstr get deallocated?
std::string FormatHelper::PadTo(std::string s, const size_t num, const char paddingChar)
{
  std::string tstr = s;
  if(num > tstr.size()) { tstr.insert(0, num - tstr.size(), paddingChar); }
  return tstr;
}

Open in new window

0
Comment
Question by:deleyd
1 Comment
 
LVL 19

Accepted Solution

by:
mrwad99 earned 250 total points
ID: 39743673
a) The local tstr is constructed from 's'
b) Because it is returned as a copy (i.e. not a reference or a pointer), a copy of tstr is made.  This copy is returned to the caller of FormatHelper::PadTo().  At this point we have two identical variables
c) The local tstr we constructed on line 3 is then destroyed when the function FormatHelper::PadTo() exits.

Now, in the caller of FormatHelper::PadTo(), if the string returned (tstr copy) is assigned to a stack allocated object, it will be destroyed when it goes out of scope.  If it is assigned to a heap allocated variable, it will only be destroyed via a call to delete.
0

Featured Post

Netscaler Common Configuration How To guides

If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.

Question has a verified solution.

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

Suggested Solutions

In days of old, returning something by value from a function in C++ was necessarily avoided because it would, invariably, involve one or even two copies of the object being created and potentially costly calls to a copy-constructor and destructor. A…
  Included as part of the C++ Standard Template Library (STL) is a collection of generic containers. Each of these containers serves a different purpose and has different pros and cons. It is often difficult to decide which container to use and …
The goal of the tutorial is to teach the user how to use functions in C++. The video will cover how to define functions, how to call functions and how to create functions prototypes. Microsoft Visual C++ 2010 Express will be used as a text editor an…
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.

832 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