Orthodox C++ (sometimes referred as C+) is minimal subset of C++ that improves C, but avoids all unnecessary things from so called Modern C++. It's exactly opposite of what Modern C++ suppose to be.
Back in late 1990 we were also modern-at-the-time C++ hipsters, and we used latest features. We told everyone also they should use those features too. Over time we learned it's unnecesary to use some language features just because they are there, or features we used proved to be bad (like RTTI, exceptions, and streams), or it backfired by unnecessary code complexity. If you think this is nonsense, just wait few more years and you'll hate Modern C++ too ("Why I don't spend time with Modern C++ anymore" archived LinkedIn article).
Code base written with Orthodox C++ limitations will be easer to understand, simpler, and it will build with older compilers. Projects written in Orthodox C++ subset will be more acceptable by other C++ projects because subset used by Orthodox C++ is unlikely to violate adopter's C++ subset preferences.
#include <stdio.h>
int main()
{
printf("hello, world\n");
return 0;
}
- C-like C++ is good start, if code doesn't require more complexity don't add unnecessary C++ complexities. In general case code should be readable to anyone who is familiar with C language.
- Don't do this, the end of "design rationale" in Orthodox C++ should be immedately after "Quite simple, and it is usable. EOF".
- Don't use exceptions.
Exception handling is the only C++ language feature which requires significant support from a complex runtime system, and it's the only C++ feature that has a runtime cost even if you don't use it – sometimes as additional hidden code at every object construction, destruction, and try block entry/exit, and always by limiting what the compiler's optimizer can do, often quite significantly. Yet C++ exception specifications are not enforced at compile time anyway, so you don't even get to know that you didn't forget to handle some error case! And on a stylistic note, the exception style of error handling doesn't mesh very well with the C style of error return codes, which causes a real schism in programming styles because a great deal of C++ code must invariably call down into underlying C libraries.
- Don't use RTTI.
- Don't use C++ runtime wrapper for C runtime includes (
<cstdio>
,<cmath>
, etc.), use C runtime instead (<stdio.h>
,<math.h>
, etc.) - Don't use stream (
<iostream>
,<stringstream>
, etc.), use printf style functions instead. - Don't use anything from STL that allocates memory, unless you don't care about memory management. See CppCon 2015: Andrei Alexandrescu "std::allocator Is to Allocation what std::vector Is to Vexation" talk, and Why many AAA gamedev studios opt out of the STL thread for more info.
- Don't use metaprogramming excessively for academic masturbation. Use it in moderation, only where necessary, and where it reduces code complexity.
- Wary of any features introduced in current standard C++, ideally wait for improvements of those feature in next iteration of standard. Example
constexpr
from C++11 became usable in C++14 (per Jason Turner cppbestpractices.com curator)
Due to lag of adoption of C++ standard by compilers, OS distributions, etc. it's usually not possible to start using new useful language features immediately. General guideline is: if current year is C++year+5 then it's safe to start selectively using C++year's features. For example, if standard is C++11, and current year >= 2016 then it's probably safe. If standard required to compile your code is C++17 and year is 2016 then obviously you're practicing "Resume Driven Development" methodology. If you're doing this for open source project, then you're not creating something others can use.
UPDATE As of January 14th 2022, Orthodox C++ committee approved use of C++17.
- Embedded C++
- Nominal C++
- Sane C++
- Why Your C++ Should Be Simple
- C++, it’s not you. It’s me.
- "Keep It C-mple" Alexander Radchenko Sydney C++ Meetup
- A dialect of C++
- Any C source that compiles with C++ compiler.
- DOOM 3 BFG
- Qt (when built with no-rtti, no-exceptions)
- dear imgui
- bgfx
- TheForge
- Oryol
- Network Next SDK
While the amount of types in here is kind of scary, I can't see how it is wrong to return
unique_ptr
when you're returning an owning pointer. That's the whole point of it, and I find it expresses the ownership quite well in this context.Oh come on, all those methods are simple helpers. If the nodes are only ever used with
unique_ptr
then it only makes sense to write them like that. You're not going to have performance problems with one-line methods in headers.Freestanding is a special case, not the normal one, and is only really intended to be used on embedded/bare-metal/kernels/etc., where most existing code would not work anyway. I was more thinking of your toolchain which you appeared to think is something appropriate for general use outside of those special circumstances.
Also, the current state of freestanding where pretty much all of the standard library is thrown out is not exactly considered to be a good thing... See also papers such as this one, which want to add a lot more features that should be able to work perfectly fine in any freestanding environment.
std::addressof
is exactly the kind of thing that basically everyone would like to see being usable in freestanding, yes. I see no reason why freestanding code should not be able to use something like that.Only if you pull in
std::make_unique
. Evenstd::default_delete
doesn't necessarily do pull it in either since it can work with a specialization ofdelete
that does not use an actual heap.You just need to remove those from a freestanding version and all is fine (at least w.r.t. containers that don't use the heap). That's what P0829 does for
std::array
,std::optional
,std::string_view
and others, btw.