对C++的一点抱怨

一段时间不写C++代码了，写起来感觉有些陌生了，特别是对于C++的模板实现更是心中没底，各种错误出现、效率底下让我不得不有些后悔当初项目采用了C++并且大量使用了STL。

然而毕竟项目已经成型，完全推倒并用纯C重构在时间上和精力上已经不太可行。选择一种语言，就像是选择一个爱人，即使后来觉得不太称心，还是要坚持到最后。好在语言的选择只是在一个项目上，随着项目的结束而结束；而爱人是一辈子，应该更加慎重抉择：）。

烦恼之余，重读大牛Linus炮轰C++的激扬文字，聊以自慰。

From: Linus Torvalds <torvalds <at> linux-foundation.org>
Subject: Re: [RFC] Convert builin-mailinfo.c to use The Better String Library.
Newsgroups: gmane.comp.version-control.git
Date: 2007-09-06 17:50:28 GMT (2 years, 14 weeks, 16 hours and 36 minutes ago)

On Wed, 5 Sep 2007, Dmitry Kakurin wrote:
> 
> When I first looked at Git source code two things struck me as odd:
> 1. Pure C as opposed to C++. No idea why. Please don‘t talk about portability,
> it‘s BS.

*YOU* are full of bullshit.

C++ is a horrible language. It‘s made more horrible by the fact that a lot 
of substandard programmers use it, to the point where it‘s much much 
easier to generate total and utter crap with it. Quite frankly, even if 
the choice of C were to do *nothing* but keep the C++ programmers out, 
that in itself would be a huge reason to use C.

In other words: the choice of C is the only sane choice. I know Miles 
Bader jokingly said "to piss you off", but it‘s actually true. I‘ve come 
to the conclusion that any programmer that would prefer the project to be 
in C++ over C is likely a programmer that I really *would* prefer to piss 
off, so that he doesn‘t come and screw up any project I‘m involved with.

C++ leads to really really bad design choices. You invariably start using 
the "nice" library features of the language like STL and Boost and other 
total and utter crap, that may "help" you program, but causes:

 - infinite amounts of pain when they don‘t work (and anybody who tells me 
   that STL and especially Boost are stable and portable is just so full 
   of BS that it‘s not even funny)

 - inefficient abstracted programming models where two years down the road 
   you notice that some abstraction wasn‘t very efficient, but now all 
   your code depends on all the nice object models around it, and you 
   cannot fix it without rewriting your app.
In other words, the only way to do good, efficient, and system-level and 
portable C++ ends up to limit yourself to all the things that are 
basically available in C. And limiting your project to C means that people 
don‘t screw that up, and also means that you get a lot of programmers that 
do actually understand low-level issues and don‘t screw things up with any 
idiotic "object model" crap.

So I‘m sorry, but for something like git, where efficiency was a primary 
objective, the "advantages" of C++ is just a huge mistake. The fact that 
we also piss off people who cannot see that is just a big additional 
advantage.

If you want a VCS that is written in C++, go play with Monotone. Really. 
They use a "real database". They use "nice object-oriented libraries". 
They use "nice C++ abstractions". And quite frankly, as a result of all 
these design decisions that sound so appealing to some CS people, the end 
result is a horrible and unmaintainable mess.

But I‘m sure you‘d like it more than git.

            Linus

From: Linus Torvalds
Subject: Re: Compiling C++ kernel module + Makefile
Date: Mon, 19 Jan 2004 22:46:23 -0800 (PST)


On Tue, 20 Jan 2004, Robin Rosenberg wrote:
> 
> This is the "We‘ve always used COBOL^H^H^H^H" argument. 

In fact, in Linux we did try C++ once already, back in 1992.

It sucks. Trust me - writing kernel code in C++ is a BLOODY STUPID IDEA.

The fact is, C++ compilers are not trustworthy. They were even worse in 
1992, but some fundamental facts haven‘t changed:

 - the whole C++ exception handling thing is fundamentally broken. It‘s 
   _especially_ broken for kernels.
 - any compiler or language that likes to hide things like memory
   allocations behind your back just isn‘t a good choice for a kernel.
 - you can write object-oriented code (useful for filesystems etc) in C, 
   _without_ the crap that is C++.

In general, I‘d say that anybody who designs his kernel modules for C++ is 
either 
 (a) looking for problems
 (b) a C++ bigot that can‘t see what he is writing is really just C anyway
 (c) was given an assignment in CS class to do so.

Feel free to make up (d).

        Linus