Tag Archives: debug

Book review : “MCSD Certification Toolkit (Exam 70-483): Programming in C#”

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Introduction

I’ve recently passed the Microsoft 70-483 “Programming in C#” certification which is one of the entry point into the .Net and WinRT developers certification cycles.
To be well prepared I’ve read the two books entirely dedicated to this certification : MCSD Certification Toolkit (Exam 70-483): Programming in C# and Exam Ref 70-483: Programming in C#.
I strongly recommend you read both of them if you intend to pass the certification.
Indeed both have been my main material to prepare for the certification and they have perfectly done the job.

This article is a complete review of MCSD Certification Toolkit (Exam 70-483): Programming in C#.
This is the first book you should read because I think this is the one that will best prepare you to get the certification, but paradoxically the worst from a technical point of view, and you will quickly understand why.

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Synchronization, memory visibility and leaky abstractions

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Introduction

First a warning, this is a difficult article which goes really deep inside the .Net machinery so if you don’t get it the first time (or even the second or third time…) don’t worry and come back later. 🙂

For a training session I’ve taught at the end of last year I wanted to demonstrate some subtleties of multi-threading, and more specifically some memory visibility issues that should cause a program to hang.
So I developed a small sample that I expected would be showing the issue, but instead of hanging as expected the program completed!

After manipulating the program further I obtained the behavior I wanted, the program was hanging, but it still didn’t explained why it managed to complete with my original version.

<SPOILER>
I suspected some JITter optimizations, and indeed it was the case, but I needed more information to completely explain this strange behavior.
As often, the StackOverflow platform was of great help; if you’re curious you can have a look at the original SO thread.
</SPOILER>

In this article I’ll “build” and explain the issue step by step, trying to make it more understandable than the SO thread which is indeed quite dry.

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If your plumbing doesn’t work you’re just not using enough pipes

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Introduction

The following article is my response to “John” comment on my other post about native C++/C# interop using C++/CLI.
The initial request was rather simple: for whatever reason John wanted to use the C++/CLI wrapper from Python and not from native C++.

It seemed technically feasible because Python has a remarkable tool to interact with native code: the ctypes module.
The only issue is that ctypes only supports C interfaces not C++ classes so in this case it can’t directly use the YahooAPIWrapper class.

In fact it’s a minor issue because this kind of situation is well known and a well documented pattern exists to circumvent it: building a C wrapper around the C++ API.

This looks a little crazy because you now have 2 layers between the Python client code and the C# Yahoo API:

Python -> C wrapper -> C++/CLI wrapper -> C# API

Puking rainbow

So, while I don’t think this layering could have any usefulness in real-life, this was a challenging and interesting question.

Looks simple no? Well, as you know when you start to pile up heterogeneous layers unexpected issues can appear and this is exactly what happened there, and it has revealed one that is worth talking about.
So keep reading!

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“If all you have is a hammer…

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…everything looks like a nail” says the proverb.

I’ll illustrate it with a little story about a common mistake I see sometimes.

(Code samples are in C# but use only basic features so C++ and Java developers should not be too disoriented.)

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Essential tools for debugging and troubleshooting : Dependency Walker aka Depends

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Introduction

This is the first article of the “Essential tools for debugging and troubleshooting” series.
Visit the series main page for more information and to discover other tools.

Dependency Walker

Dependency walker (a.k.a Depends) is a simple yet powerful tool that you’ll find invaluable if you have to track the native dependencies of your components (EXE or DLL).
Dependency Walker can be used for static (without having to run any code) or dynamic analysis (with dependencies tracked while running your code).

I’ll illustrate its usefulness with a from scratch sample.
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