Best CppCon 2016 Talks?
This is a useful Reddit thread for those looking for suggestions on where to start, or just what highlights they might have missed so far, in the >100 CppCon 2016 videos...
Best CppCon 2016 Talks?
38 C++ User Group Meetings in November
The monthly overview on upcoming C++ User Group meetings
C++ User Group meetings in November 2016
by Jens Weller
From the article:
This month features 38 C++ User Group meetings already! Plus several C++ Conferences, including Meeting C++ 2016! I included since this month also the LLVM groups which are meeting, there are a few. This is why this month has also 12 new User Groups, with the latest additions of a new group in London and Melbourne!
There are 12 new C++ User Groups: Kitchener, OT, Brussels, Cluj (Qt), Berlin (llvm), St. Petersburg (llvm), Paris (llvm), Bay area (llvm), Cambridge (llvm), Denver, Minsk, London and Melbourne.
C++ Weekly Episode 35: Reading Assembly Language - Part 2—Jason Turner
Episode 35 of C++ Weekly.
Reading Assembly Language - Part 2
by Jason Turner
About the show:
In this episode Jason continues his brief introduction to reading the assembly language output that your compiler can generate.
Finding bugs in the code of LLVM project with the help of PVS-Studio
Let's take a look at the suspicious fragments in the LLVM code which PVS-Studio detected.
Finding bugs in the code of LLVM project with the help of PVS-Studio
by Andrey Karpov
From the article:
LLVM developers, of course, will be able to understand if there is a bug here or not. I have to play detective. Looking at the code, I was thinking in the following direction: The function should read the opening bracket '<', then it reads the identifiers and commas in the loop. If there is no comma, we expected a closing bracket. If something goes wrong, then the function returns an error code. I reckon there was supposed to be the following algorithm of the function work (pseudocode).
N4615: WG21 2016-10-28 Telecon Minutes -- Jonathan Wakely
A new WG21 paper is available. If you are not a committee member, please use the comments section below or the std-proposals forum for public discussion.
Document number: N4615
Date: 2016-10-28
WG21 2016-10-28 Telecon Minutes
by Jonathan Wakely
CppCast Episode 76: Embedded Development with Dan Saks
Episode 76 of CppCast the only podcast for C++ developers by C++ developers. In this episode Rob and Jason are joined by Dan Saks from Saks & Associates to discuss state of C++ in the embedded development industry.
CppCast Episode 76: Embedded Development with Dan Saks
by Rob Irving and Jason Turner
About the interviewee:
Dan Saks is the president of Saks & Associates, which offers training and consulting in C and C++ and their use in developing embedded systems. He has been a columnist for The C/C++ Users Journal, The C++ Report, Embedded Systems Design, embedded.com and several other publications. Dan served as the first secretary of the C++ Standards Committee and contributed to the CERT Secure Coding Standards for C and C++.
Modern C++ Features – User-Defined Literals--Arne Mertz
Learn more about litterals.
Modern C++ Features – User-Defined Literals
by Arne Mertz
From the article:
User-defined literals are a convenient feature added in C++11.
C++ always had a number of built-in ways to write literals: Pieces of source code that have a specific type and value. They are part of the basic building blocks of the language:
32 043 0x34 //integer literals, type int 4.27 5E1 //floating point literals, type double 'f', '\n' //character literals, type char "foo" //string literal, type const char[4] true, false //boolean literals, type boolThese are only the most common ones, there are many more, including some newcomers in the newer standards. Other literals are nullptr and different kinds of prefixes for character and string literals. There also are suffixes we can use to change the type of a built-in numeric literal:
32u //unsigned int 043l //long 0x34ull //unsigned long long 4.27f //float 5E1l //long double
void foo(T& out) - How to fix output parameters--Jonathan Müller
Or how to improve readability and reduce errors.
void foo(T& out) - How to fix output parameters
by Jonathan Müller
From the article:
There are some cases where you need to return a value from a function but cannot use the return value. It happens, for example, in functions where you want to return multiple values at once. While you can pass multiple inputs to a function - the parameters, you cannot pass multiple return values in the same way.
C++ programmers tend to use a good old (lvalue) reference for that. You take a non-const reference as parameter and assign the output to that reference. The caller will pass a variable and upon function completion find the value of the variable changed.
Yet this approach has some problems: For starters, it is not obvious when just looking at the call that the variable is going to be changed. This is the reason that C++ style guides such as the one used by Google recommend using a pointer for that. The caller then has to explicitly pass in the address of the variable, making it explicit.
But with a pointer you can now pass in nullptr, you have to check for that in the function: A pointer where you really mean “reference” does not follow the guidelines I’ve been advocating for.
So is there not a universal solution?
There is, but first we need to understand the full scope of the problem.
Quick Q: Is std::vector so much slower than plain arrays?
Quick A: A vector isn’t slower than an array when they do the same things. But it lets you do much more…
Some time ago on SO:
Is std::vector so much slower than plain arrays?
Using the following:
g++ -O3 Time.cpp -I <MyBoost>
./a.out
UseArray completed in 2.196 seconds
UseVector completed in 4.412 seconds
UseVectorPushBack completed in 8.017 seconds
The whole thing completed in 14.626 seconds
So array is twice as quick as vector.But after looking at the code in more detail this is expected; as you run across the vector twice and the array only once. Note: when you
resize()the vector you are not only allocating the memory but also running through the vector and calling the constructor on each member.Re-Arranging the code slightly so that the vector only initializes each object once:
std::vector<Pixel> pixels(dimensions * dimensions, Pixel(255,0,0));Now doing the same timing again:
g++ -O3 Time.cpp -I <MyBoost>
./a.out
UseVector completed in 2.216 seconds
The vector now performance only slightly worse than the array. IMO this difference is insignificant and could be caused by a whole bunch of things not associated with the test.I would also take into account that you are not correctly initializing/Destroying the Pixel object in the
UseArrray()method as neither constructor/destructor is not called (this may not be an issue for this simple class but anything slightly more complex (ie with pointers or members with pointers) will cause problems.
Presenting Code
How should we present code? - is the question.
Presenting Code
by Jens Weller
From the article:
At CppCon 2015 I decided to give a small lightning talk on how to present code in the coming year. This was a reflection on visiting many C++ related conferences and seeing many talks live and online...