Skip to main content

g++ compiler option -Weffc++

I found it quite interesting to know that g++ compiler actually provides an option (-Weffc++) which enables warnings for constructs that violate guidelines in Effective C++!!

From g++ manual (man g++)
== Begin ==
Warn about violations of the following style guidelines from Scott Meyers’ Effective C++ book:

* Item 11: Define a copy constructor and an assignment operator for classes with dynamically allocated memory.
* Item 12: Prefer initialization to assignment in constructors.
* Item 14: Make destructors virtual in base classes.
* Item 15: Have "operator=" return a reference to *this.
* Item 23: Don’t try to return a reference when you must return an object.

Also warn about violations of the following style guidelines from Scott Meyers’ More Effective C++ book:

* Item 6: Distinguish between prefix and postfix forms of increment and decrement operators.
* Item 7: Never overload "&&", "││", or ",".

When selecting this option, be aware that the standard library headers do not obey all of these guidelines.

== End ==

Indeed, Effective C++ is a very nice work by Scott Meyer. He has compiled two lists of top C++ publications: top 5 books and top 5 articles. His list captures right set of very well written, excellent publications in C++ as I have read most of the literature in those lists. I would also like to add More C++ Gems to that list.

Comments

Anonymous said…
Cool!! I never heard that before
Sat Jan 13, 06:35:00 PM PST
florin said…
it's a nice flag but it outputs way too many warnings: if you have a string as a member of a class and you don't care to call its constructor (because you know that the default constructor will be called), you'll get an useless warning;

it should have a switch to disable warnings for objects (or at least for the STL classes like strings).
Tue May 24, 02:09:00 AM PDT
r2p2 said…
@florin I didn't know about this flag until this post. But I already initialize all my member variables. I think it is the best way to be sure before some M$ compilers will break it. :D

Hope it is readable english. =)
Tue Sep 06, 05:49:00 AM PDT
Anonymous said…
thanks for sharing

gclub
Sat Jun 24, 10:03:00 AM PDT
Post a Comment

Popular Content

Multi-dimensional arrays in C++11

What new can be said about multi-dimensional arrays in C++? As it turns out, quite a bit! With the advent of C++11, we get new standard library class std::array. We also get new language features, such as template aliases and variadic templates. So I'll talk about interesting ways in which they come together. It all started with a simple question of how to define a multi-dimensional std::array. It is a great example of deceptively simple things. Are the following the two arrays identical except that one is native and the other one is std::array? int native[3][4]; std::array<std::array<int, 3>, 4> arr; No! They are not. In fact, arr is more like an int[4][3]. Note the difference in the array subscripts. The native array is an array of 3 elements where every element is itself an array of 4 integers. 3 rows and 4 columns. If you want a std::array with the same layout, what you really need is: std::array<std::array<int, 4>, 3> arr; That's quite annoying for
22 comments
Read more

Unit Testing C++ Templates and Mock Injection Using Traits

Unit testing your template code comes up from time to time. (You test your templates, right?) Some templates are easy to test. No others. Sometimes it's not clear how to about injecting mock code into the template code that's under test. I've seen several reasons why code injection becomes challenging. Here I've outlined some examples below with roughly increasing code injection difficulty. Template accepts a type argument and an object of the same type by reference in constructor Template accepts a type argument. Makes a copy of the constructor argument or simply does not take one Template accepts a type argument and instantiates multiple interrelated templates without virtual functions Lets start with the easy ones. Template accepts a type argument and an object of the same type by reference in constructor This one appears straight-forward because the unit test simply instantiates the template under test with a mock type. Some assertion might be tested in
Post a Comment
Read more

Want speed? Use constexpr meta-programming!

It's official: C++11 has two meta-programming languages embedded in it! One is based on templates and other one using constexpr . Templates have been extensively used for meta-programming in C++03. C++11 now gives you one more option of writing compile-time meta-programs using constexpr . The capabilities differ, however. The meta-programming language that uses templates was discovered accidently and since then countless techniques have been developed. It is a pure functional language which allows you to manipulate compile-time integral literals and types but not floating point literals. Most people find the syntax of template meta-programming quite abominable because meta-functions must be implemented as structures and nested typedefs. Compile-time performance is also a pain point for this language feature. The generalized constant expressions (constexpr for short) feature allows C++11 compiler to peek into the implementation of a function (even classes) and perform optimization
37 comments
Read more