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There is a well-known problem with exceptions in C++ constructors. Only objects that are constructed completely are deleted in C++. Usually, the developer is supposed to take special measures against the possible memory leaks. So let us look into what Symbian offers and what else can be done to solve the issue.

Suppose, there is a class:

class Container

{

                public:

                               Container ()

{

               thePart1 = new Part1();              

               thePart2 = new Part2();

};

                               ~Container()

{

               delete thePart1;

               delete thePart2;

 

};

                private:

                               Part1 *thePart1;

                               Part2 *thePart2;

}

If object c of the Container class is being created as a local object:

 

 void test ()

{

                Container c();

                …

}

and the exception  arises on c construction, then c’s  destructor is not called.

The results are that Part 1  and/or Part 2 are not deleted, and a memory leak takes place.

Symbian proposes to push the pointer to the newly created object onto the special stack – the so-called clean-up stack. In case of an exception, the clean-up stack is unwinded, and every pointer on it is deleted. So we could redesign our constructor the following way (for Symbian):

Container::Container ()

{

                               thePart1 = new Part1();              

                               CleanupStack::PushL(thePart1);

                               thePart2 = new Part2();

                               CleanupStack::Pop(thePart1);

};

Of course, it works and looks better than:

Container::Container ()

{

try{

                                               thePart1 = new Part1();              

                                               thePart2 = new Part2();

                                     }       

                               catch (…)

                                               {

                                                               delete thePart1;

                                                               delete thePart2;

}

};

 

But it could be made easier and more elegant by changing the pointers to smart pointers:

class Container

{

                public:

                               Container ()

{

               thePart1 = new Part1();              

               thePart2 = new Part2();

};

                               ~Container()

{

// nothing to do!!

};

                private:

                               auto_ptr<Part1> thePart1;

                               auto_ptr<Part2> thePart2;

}

 

Thus, we decrease the risk of memory leaks on exceptions. At the same time, we don’t have to release our resources in the constructor. It seems like we don’t need to use CleanupStack in Symbian at all – just develop an auto_ptr class instead:

template<class T>

class auto_ptr

{

                public:

                               auto_ptr (T *p = 0): ptr(p) {}

                               ~auto_ptr() {delete ptr;}

                private:

                               T *ptr;

}

Murano Software teams are comprised of dozens of skilled and experienced engineers. Every day, they face new challenges while developing our clients’ software products. The ability to find the right solution to a problem is one of the crucial elements that influence performance, readability, scalability, completeness and other qualities of a software product.

Since there are a lot of technology companies among Murano Software’s clients, the ways that our engineers solve diverse issues can be of high interest to our readers. We will cover the challenges with .NET, Java, Ajax, Ruby on Rails, SharePoint and other technologies.

You are welcome to comment on the posts. Our developers will be happy to share their experiences and discuss the issues.

Today, we start with Exceptions in Symbian C++ Constructors.

In the IT sphere, high quality of a product heavily depends on the abilities of its creators. According to many analysts, the number of companies that decide to outsource their search for high quality developers is increasing. That is why we will start our blog post series by looking into the quality of the technology resources that can be found in Russia.

As the Business Line columnist Vipin V. Nair notices, “Russia draws its software strength from its enormously talented pool of people.” In Russia, the abilities of IT developers are significantly enhanced by an extremely strong educational system, which is recognized all over the world. While, for example, “In India, students learn generic software skills, Russian students are taught advanced mathematical and computing techniques, which allows them to perform hard-core technical work,” says Vipin V. Nair. More than 40% of university degrees in Russia are in technology and science.

Russian software companies do not miss the opportunity to leverage that great manpower. According to a research paper by Market-Vision / EDC, 77.4% of Russian software companies employ PhDs, and in 45.8% of those companies, PhDs make up 10% or more of their staff. So by dealing with Russian outsourcing vendors, you get the opportunity to benefit from employing these highly educated engineers.  

Russian developers’ strengths are recognized by local market tech circles and global ones as well. A 2006 study by the FCREUE, the Haas School of Business and the UniversityCalifornia concluded, “In terms of education and experience with complex software development tasks, Russian programmers are likely to outrank all others.” of

Most analysts stress that very capability of Russian developers to manage tasks of high complexity and to find fresh and groundbreaking solutions to knotty problems. “Exceptionally well-educated developers who can perform extremely complex jobs, and a great understanding of engineering and financial services domains, are core strengths of Russia's outsourcing industry,” remarks William Martorelli, principal analyst at Forrester.

According to another study run by by Ernst & Young, Russia beats several other outsourcing locations in terms of skills and training of its IT workforce. You can see Russia’s top position from this table.

One of the ways for specialists to prove their knowledge and skills is to partake in high-profile contests. Russian technology students regularly win international programming contests. Russia has won the world's most prestigious competition, the Association of Computing Machinery (ACM) International Collegiate Programming Contest, 5 times over the last 10 years. For comparison, the USA has taken the first place only once over the same period, while India has not appeared on the top of this contest at all.

When reading this article, you may think, “Well, the Russian resources are talented, but their number is probably more limited to choose from, than, for example, in India.” Then here is some data for you. As it is written in the paper on BRIC layers by Economic Research from the GS Institutional Portal, Russia, being almost 80% smaller by population than India, its main competitor, produces even more tertiary graduates (16,765 graduates in Russia to 16,095 in India). In per capita terms, Russia has by far more graduates when compared to India (115 graduates per capita in Russia to 16 graduates per capita in India). As for technical PhDs, Russia has almost as many of them as Germany does and even in absolute terms leaves India far behind (about 12,000 technical PhDs in Russia to about 5,000 of them in India). Russia also outranks India in the number of workers with tertiary qualifications in science and engineering. Thus, you are sure to find in Russia enough specialists for all your projects to be realized.

Nowadays, Russia is increasingly considered one of the most attractive outsourcing destinations. SAP, Microsoft, IBM, Google, Boeing, Motorola, Reuters and IBM are only a few of the many global companies that employ local engineers and set up development centers in Russia. eWEEK named the Russian outsourcing industry as one gaining maturity and showing promise. The Indian outsourcing industry has to watch out, Business Line warns. Russia attracts technology outsourcing buyers, global companies and start-ups for a number of reasons.

The most substantial reason is a wide pool of talent with a high level of proficiency in diverse realms. “High-level thinking, strong English skills among key staff and executives, and a desire to break new ground on leading-edge projects are intrinsic to the Russian developers," says the eWEEK columnist Stan Gibson. This benefit is successfully combined with the lower cost and attrition rate that Russia offers.

There are also secondary factors that influence tech directors’ decision to outsource software development projects to Russia. Among them is cultural affinity of Russians with Americans and Europeans, the individual approach of Russian companies toward clients, the creativity and collaborative thinking of Russian developers, the Russian government’s new positive attitude toward offshore software development.

These factors can greatly influence your choice of where to assemble your offshore software development team. To make your choice easier, here, in our blog, we will publish a series of posts casting light on the reasons for outsourcing to Russia.