Questions tagged [c++]
For questions about C++'s design, or languages which are closely related to C++
35 questions
7
votes
1
answer
841
views
Why might C++ have been designed to make types like std::strong_ordering a class instead of an enumeration?
In C++, std::strong_ordering has four valid values, yet instead of being an enumeration, it is a class. This seems weird to me, for it prevents std::strong_ordering from being used in a switch ...
- 495
-4
votes
3
answers
188
views
Did std::forward_list really need *_after member functions?
Did C++'s std::forward_list really need insert_after, emplace_after, ...
- 1,485
8
votes
0
answers
151
views
Non-trivial implementations of consume memory ordering
In the C++ memory model through C++23, one of the memory ordering types for loads is memory_order_consume. The intent of this was to expose the feature that most ...
- 1,096
0
votes
1
answer
219
views
Why does C++ let some standard class templates lack definitions when not specialized, rather than to explicitly let them be unusable by default?
In the standard C++ library, some class templates lack definition, but are defined when their template is specialized. The most notable such class template is ...
- 1,485
-2
votes
2
answers
224
views
Parallel like CUDA, safe like Rust [closed]
CUDA excels at parallel programming, but is primarily marketed for programming languages that have certain disadvantages compared to Rust, for example in terms of safety (C, C++) or speed (Python).
...
- 97
7
votes
3
answers
1k
views
What aspects of a language design make copyability of an object possible or conditional to something?
I was reviewing the so-called prototype pattern, and I feel like in C++ it all boils down to "how do I define a virtual copy constructor" (and if you ...
- 175
-1
votes
2
answers
546
views
If in computer science, compare-and-swap is known as "compare-and-swap," why are the C/C++ functions named atomic_compare_exchange_*?
In computer science, compare-and-swap is known as, well, "compare-and-swap" and often abbreviated as "CAS."
Why are the functions in the standard C library and C++ library named <...
- 404
7
votes
2
answers
343
views
Why can't a parser for C++ be realized with a DPDA?
In the book of Wilhelm, Seidl and Hack, " Compiler Design, Syntactic and Semantic Analysis" they write on p. 10 (bold face emphasis is mine)
Most designers of programming languages have ...
- 173
3
votes
1
answer
255
views
Is there any particular reason to only implement 2 and 3 input hypot?
I've checked the information on cppreference.com and found that there are only 2 and 3 input hypot function. I am wondering why not implement the variadic version ...
- 165
0
votes
1
answer
429
views
How might I implement a `typeid` operator (returning the type of its argument as something, presumably as a string) in my compiler?
So, here is how strings work in my AEC-to-WebAssembly compiler. After the program is parsed, all strings except inline assembly ones are gathered in a C++ ...
- 2,337
12
votes
0
answers
486
views
In C/C++, why does the logarithm of zero have a well-defined imaginary part?
By the C standard and the C++ standard:
$\log(0+0i) = -\infty+0 i$.
$\log(0-0i) = -\infty-0 i$.
$\log(-0+0i) = -\infty+\pi i$.
$\log(-0-0i) = -\infty-\pi i$.
However, if the floating-point complex ...
- 1,485
11
votes
0
answers
484
views
Why was && chosen as rvalue reference in C++?
I am NOT asking what && means.
Does anyone know the history of why the symbol && was chosen? I can give some ...
16
votes
7
answers
6k
views
How is clang able to evaluate loops without getting stuck in an infinite loop?
I recently saw this tweet.
And for posterity, this is the C++ code:
...
- 263
9
votes
1
answer
2k
views
Why did std::set not have a contains function until C++20?
Another design decision that baffled me. Checking if an element is in a set is the entire purpose of a set! Until C++20 I had to write stuff like ...
- 591
16
votes
3
answers
5k
views
Why did C++ standard library name the containers map and unordered_map instead of map and ordered_map?
This is something that has slightly annoyed me for a while. A map as a mathematical object (function) is by default "unordered", and the same is for maps as a data structure AKA associative ...
- 591