In programming, memory leaks are a common issue, and it occurs when a computer uses memory but does not give it back to the operating system. Experienced programmers have the ability to diagnose a leak based on the symptoms. Some believe every undesired increase in memory usage is a memory leak, but this is not an accurate representation of a leak. Certain leaks only run for a short time and are virtually undetectable.

Memory Leak Consequences

Applications that suffer severe memory leaks will eventually exceed the memory resulting in a severe slowdown or a termination of the application.

How to Protect Code from Memory Leaks?

Preventing memory leaks in the first place is more convenient than trying to locate the leak later. To do this, you can use defensive programming techniques such as smart pointers for C++.  A smart pointer is safer than a raw pointer because it provides augmented behavior that raw pointers do not have. This includes garbage collection and checking for nulls.

If you are going to use a raw pointer, avoid operations that are dangerous for specific contexts. This means pointer arithmetic and pointer copying. Smart pointers use a reference count for the object being referred to. Once the reference count reaches zero, the excess goes into garbage collection. The most commonly used smart pointer is shared_ptr from the TR1 extensions of the C++ standard library.

Static Analysis

The second approach to memory leaks is referred to as static analysis and attempts to detect errors in your source-code. CodeSonar is one of the effective tools for detection. It provides checkers for the Power of Ten coding rules, and it is especially competent at procedural analysis. However, some might find it lagging for bigger code bases.

How to Handle a Memory Leak

For some memory leaks, the only solution is to read through the code to find and correct the error. Another one of the common approaches to C++ is to use RAII, which an acronym for Resource Acquisition Is Initialization. This approach means associating scoped objects using the acquired resources, which automatically releases the resources when the objects are no longer within scope. RAII has the advantage of knowing when objects exist and when they do not. This gives it a distinct advantage over garbage collection. Regardless, RAII is not always recommended because some situations require ordinary pointers to manage raw memory and increase performance. Use it with caution.

The Most Serious Leaks

Urgency of a leak depends on the situation, and where the leak has occurred in the operating system. Additionally, it becomes more urgent if the leak occurs where the memory is limited such as in embedded systems and portable devices.

To protect code from memory leaks, people have to stay vigilant and avoid codes that could result in a leak. Memory leaks continue until someone turns the system off, which makes the memory available again, but the slow process of a leak can eventually prejudice a machine that normally runs correctly.

Related:

The Five Principles of Performance

In Demand IT Skills

Technology is wonderful. It helps us run our businesses and connects us to the world. But when computer problems get in the way of getting what you need to get done, you can go from easygoing to mad-as-a-hornet in 3 seconds flat. Before you panic or give in to the temptation to throw your computer out the window, try these easy fixes.

5 Common Computer Problems

1. Sluggish PC

A sluggish PC often means low disk space caused by an accumulation of temporary Internet files, photos, music, and downloads. One of the easiest fixes for a slow PC is to clear your cache.

The way you’ll do this will depend on the Internet browser you use:

• Chrome– On the top right-hand side of the screen, you’ll see what looks like a window blind. Click on that. Click on ‘History’ and hit ‘Clear Browsing Data’.

• Safari– On the upper left-hand side, you’ll see a tab marked ‘Safari’. Click on that. Scroll down and hit ‘Empty Cache’.

• Internet Explorer– Click on ‘Tools’ and scroll down to ‘Internet Options’. Under ‘Browsing History’ click ‘Delete’. Delete files and cookies.

• FireFox – At the top of the window click ‘Tools’ then go to ‘Options’. Select the ‘Advanced’ panel and click on the ‘Network’ tab. Go to ‘Cached Web Content’ and hit ‘Clear Now’.

The python keyword global is used in a function to distinguish a local representation of a variable with the same name. 

glbvar = 0

def setglbvar():
    global glbvar # include this declaration so that updates to glbvar are NOT LOCAL to this function
    glbvar = 1

def printglbvar():
    print glbvar     # No need for global declaration to read value of globvar

setglbvar()
printglbvar()       # Prints 1

The consulting industry is fiercely competitive and nets between $130B and $150B a year. In fact, professional consultants earn more money than many lawyers, doctors and other professionals. 

Offering free consultations is a common way for a software consultant to seize new accounts. But is there a red flag where a consultant may be giving away too many services for free? The worst scenario for a professional software consultant is to offer free services to the client and then never hear from them again once they no longer need their help. 

Although having the best intentions, many people will waste a consultant's time (i.e., client ignores or rejects any suggested approaches or solutions given by the consultant and seek the services of someone who will do it cheaper or will attempt to do it themselves). Small business owners especially can be challenging to work with. Some clients have a tendency to jump into projects before having adequate resources to finish what they have started, decide to go in a different direction midstream, while others simply don't want to spend any money when getting professional services. It's hard to believe, but some clients actually expect to receive free services for life. To counteract this notion, a software consultant can draw the line by offering free services within a promotional time frame and then begin charging a fee for services rendered after that time.

A good indicator of what a client's true intentions are is to monitor their activity within a specified period to see if their consultation activity bears fruit in the form of a contract. One big red flag is non-commitment on the part of the client. If they seem indecisive or vague about what they want it may be time to move on. Although there are times when a free consultation results in a paying client years later, who can wait that long? 

Less of Your Time is Wasted When You're Upfront

After being burned, some professional software consultants no longer give free consulting. They find that clients are much more willing to follow their advice when they have paid something. In order to close an account, a happy medium can be agreed upon by both parties involved as a way to build a long term relationship with highly qualified prospects. 

A software consultant's work, knowledge, skills and time are valuable. They can offer a potential client general solutions instead of addressing specific challenges. If a specific topic of discussion, troubleshooting session or other issue needs to be addressed, the consultant can inform the client of any upfront costs to receive a particular service if they need further assistance. Really, a free software consultation (if one is given) should be presented in a very similar way someone would hand out samples of a product at a grocery store. A professional consultant ideally wants clients to see how they can benefit using their services on a trial basis with a pitch leading to more extensive services which would only be available if they sign a contract with their firm. 

 Red Flags