The compiler is to blame for everything -- Andrey Karpov

By Andrey Karpov | Jun 4, 2015 11:48 PM | Tags: errors compilers compiler bugs basics

Many programmers are very fond of blaming the compiler for different errors. Let's talk about it.

The compiler is to blame for everything

by Andrey Karpov

From the article:

When a programmer tells you that the compiler causes an error, it is a lie in 99% of cases. When you start investigating the problem, you usually find out the following reasons:

• an array overrun;
• an uninitialized variable;
• a misprint;
• a synchronization error in a parallel program;
• a non-volatile variable used;
• code leading to undefined behavior;
• etc.

Simple C++11 metaprogramming--Peter Dimov

By Adrien Hamelin | Jun 2, 2015 12:05 PM | Tags: c++14 advanced

If you like to play with templates, read this article:

Simple C++11 metaprogramming

by Peter Dimov

From the article:

The wide acceptance of Boost.MPL made C++ metaprogramming seem a solved problem. Perhaps MPL wasn't ideal, but it was good enough to the point that there wasn't really a need to seek or produce alternatives.

C++11 changed the playing field. The addition of variadic templates with their associated parameter packs added a compile-time list of types structure directly into the language...

Holier Than Thou--Tony “Bulldozer00” (BD00) DaSilva

By Adrien Hamelin | Jun 2, 2015 11:51 AM | Tags: advanced

A rare but possible problem that can occur with long running programs:

Holier Than Thou

by Tony DaSilva

From the article:

Since C++ (by deliberate design) does not include a native garbage collector or memory compactor, programs that perform dynamic memory allocation and de-allocation (via explicit or implicit use of the “new” and “delete” operators) cause small “holes” to accumulate in the free store over time. I guess you can say that C++ is “holier than thou“. :( ...

docopt.cpp: A C++11 Port--Jared Grubb

By Adrien Hamelin | Jun 1, 2015 08:02 AM | Tags: intermediate efficiency

A nice library to help you ship a program:

docopt.cpp: A C++11 Port

by Jared Grubb

From the article:

Isn't it awesome how getopt (and boost::program_options for you fancy folk!) generate help messages based on your code?! These timeless functions have been around for decades and have proven we don't need anything better, right?

Hell no! You know what's awesome? It's when the option parser is generated based on the beautiful help message that you write yourself! This way you don't need to write this stupid repeatable parser-code, and instead can write only the help message--the way you want it...

How to implement a stateful meta-container in C++ -- Filip Roséen

By Mantosh Kumar | May 28, 2015 09:27 PM | Tags: experimental c++14 advanced

Implementing stateful meta contianer in C++ Using Modern C++.

How to implement a stateful meta-container in C++

by Filip Roséen

From the article:

This post has explained the technical aspects related to an implementation of a stateful meta-container, allowing a developer to more easily work with, and modify, a given set of entities during the phase of translation.

Together with the previous posts in this series, the formerly unstateful world of translation has gone into a stateful universe — allowing for some crazy, but conforming, implementations.

Quick Q: Why are override and final identifiers with special meaning instead of reserved keywords?

By Adrien Hamelin | May 28, 2015 02:31 PM | Tags: c++11 basics

Quick A: To avoid breaking old code, thanks to context-sensitive keywords.

Recently on SO:

Why are override and final identifiers with special meaning instead of reserved keywords?

Both the override specifier and final specifier were added in C++11. They differ from other specifiers added to C++11 such as constexpr and decltype, in that they are not keywords and so are available for use as identifiers:

int main()
{
  int override = 0 ;    // Ok
  int final = 0 ;       // Ok
  //int constexpr = 0 ; // Error
}

They are referred to as identifiers with special meaning, which is covered in the draft C++11 standard section 2.11 [lex.name] (emphasis mine):

The identifiers in Table 3 have a special meaning when appearing in a certain context. When referred to in the grammar, these identifiers are used explicitly rather than using the identifier grammar production. any ambiguity as to whether a given identifier has a special meaning is resolved to interpret the token as a regular identifier.
and Table 3 -- Identifiers with special meaning lists both override and final.

Why did these two specifiers end up being identifiers with special meaning instead of keywords?

New C++ experimental feature: The tadpole operators--Raymond Chen

By Adrien Hamelin | May 28, 2015 02:23 PM | Tags: intermediate experimental

You should read about this amazing new feature:

New C++ experimental feature: The tadpole operators

by Raymond Chen

From the article:

How often have you had to write code like this:

x = (y + 1) % 10;
x = (y + 1) * (z - 1);
x = (wcslen(s) + 1) * sizeof(wchar_t);

Since the + and - operators have such low precedence, you end up having to parenthesize them a lot, which can lead to heavily nested code that is hard to read...

Once you have been thoroughly amazed, you should also read this article:

The tadpole operators explained

Cling Aims to Provide a High-performance C++ REPL--Sergio De Simone

By Adrien Hamelin | May 28, 2015 02:14 PM | Tags: intermediate efficiency

Read about a REPL allowing to test things rapidly in C++:

Cling Aims to Provide a High-performance C++ REPL

by Sergio De Simone

From the article:

Cling is an interactive C++ interpreter that is built on top of LLVM and Clang and promises to provide a leap in productivity by going beyond the usual code-compile-run-debug C++ workflow...

Other useful materials:

• A short introduction video (youtube link)
• An article about C++ and scripting

C++17 Fold Expressions--Baptiste Wicht

By Adrien Hamelin | May 27, 2015 01:24 PM | Tags: intermediate experimental

You should read that if you want to know more about this exciting future feature of C++:

C++17 Fold Expressions

by Baptiste Wicht

From the article:

C++11 introduced variadic template to the languages. This new feature allows to write template functions and classes taking an arbitrary number of template parameters. This a feature I really like and I already used it quite a lot in my different libraries. Here is a very simple example computing the sum of the parameters:

// Good with variadics
auto old_sum(){
    return 0;
}

template<typename T1, typename... T>
auto old_sum(T1 s, T... ts){
    return s + old_sum(ts...);;
} 

// Better with fold expressions
template<typename... T>
auto fold_sum_1(T... s){
    return (... + s);
}x

Did you know? - STL algorithms and comparators

By Adrien Hamelin | May 26, 2015 08:00 AM | Tags: performance basics

Did you know?

The way the STL takes comparators is not the better thing in some cases, like with the following comparator:

[] (const T& a, const T& b) { return expensive_function(a) < expensive_function(b); }

Check it out.