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C Strings and my slow descent to madness

deusinmachina.net

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Re: C Strings and my slow descent to madness

#191

Post by lolcatuser »

nerdponx wrote: post #53
bluetomcat wrote: post #24

Earlier quoted context omitted.

The best way to write C is to treat strings as memory locations with characters and nothing more. Every such memory location has an allocated size, either statically at compile-time (with literals and arrays), or dynamically with malloc and friends. Treat string operations as mere memory operations and don't imagine them to be something else. The str* functions from the standard library are just convenience helpers w…

Maybe you could summarize this by saying that C strings are "strings of bytes", not "strings of characters".

It's better to say that, in C, characters are bytes. That's why coming at this from the modern perspective of "characters are the things on my screen" is always going to confuse you - C doesn't have bytes, only characters. C programmers (should) understand this the same way Lisp programmers understand that "CAR" and "CDR" refer to "first" and "rest" or Forth programmers understand that "the stack" is the data stack and has no relation to the call stack.

Re: C Strings and my slow descent to madness

#192

Post by gaws »

stephc_int13 wrote: post #31

If you are using C and do some non-trivial work with strings you should either use a good library to handle strings or build your own. It is not that difficult in practice. The old C std lib is, in my opinion, outdated, obsolete and a very bad fit for complex string handling, especially on the memory management side. In my own framework, the string management module is using a dedicated memory allocator and a "high l…

> use a good library

Such as?

Re: C Strings and my slow descent to madness

#193

Post by gaws »

userbinator wrote: post #7

Well-written C tends to minimise string usage in general, preferring to convert to another format as soon as possible. Allocating, copying, and passing around strings in large quantities is not a good idea for efficiency, but of course some people coming from other HLLs seem to try to do it anyway, which causes many other problems.

> preferring to convert to another format as soon as possible.

Like what?

Re: C Strings and my slow descent to madness

#195

Post by kovac »

tragomaskhalos wrote: post #176

K&R contains this beautiful koan-like string copy code: while (*t++ = *s++) ; Honestly the elegance of this thing was one of the hooks that made me fall in love with C. But this was from a now-forgotten age of innocence, as there are so many "nopes" around this line-and-a-half that one would, rightly, be tarred and feathered for ever putting it in a program today.

Could you explain why this line should be discouraged? I'm a beginner in C, so I really don't know. That's why I'm asking.

Re: C Strings and my slow descent to madness

#196

Post by lmm »

simonblack wrote: post #174

"We're not in Kansas any more, Toto" Or to paraphrase that "We're not in Python any more, and C is not Python". You know what sends me insane? Indentation and lack of fixed types in Python. But I don't have problems with C strings. Because I have grown to love and know C's string foibles just like the author will certainly not be driven insane by 'Python's shortcomings according to me'. The world is full of people wh…

Indentation and lack of fixed types aren't responsible for over 50% of known security issues in software.

C's issue are not just harmless foibles. They cause real harm to the poor people actually using the software.

Re: C Strings and my slow descent to madness

#197

Post by kovac »

_benj wrote: post #35
felipemnoa wrote: post #12

Earlier quoted context omitted.

>>I’ve also been having a blast with C because writing C feels like being a god Not trying to be a troll but as someone who has also written a lot of C in the past why do you feel like this?

It’s the access and control that it gives me! As when I’d pick Go because I was doing some concurrency, I can now explore a bunch of concurrency libraries, including some implementations that look a lot like Go channels. Want to watch a file for changes? I can do that all the way from taking to the kernel to picking a multi-platform library. I guess, I haven’t really found anything that I can’t do in C, and if I’m la…

I came from HLL like C# and I've come to love C for the same reasons. The only language I can fit in my head in its entirety and no one telling me this is the "right way" to write code, don't use this or that feature, etc. When I'm writing C, I am free. I absolutely love this freedom!

Re: C Strings and my slow descent to madness

#198

Post by asveikau »

stephc_int13 wrote: post #183
asveikau wrote: post #179

Earlier quoted context omitted.

Nintendo DS has probably had a lot less scrutiny than a major libc or recent GCC or clang [though you can probably target its ARM processor with that]. Also, for an older embedded platform they may choose to do optimization for code size rather than cycles or clock time. I'm going to have to doubt the start of your comment. Having seen a lot of libc implementations I think you are better off not wasting time optimizi…

On the contrary, I expected the Nintendo DS SDK to be well optimized, performance of memcpy can be critical on such a constrained hardware. And it was optimized, just not with the best tricks. I got the prefetching trick from Intel source code, except that I replaced the PLD instruction by a simple dummy load. And about strlen, you'd be surprised, some implems are very good, and some are not, depends on the compiler…

I think this expectation doesn't vibe with my understanding of how people used to think about embedded or consoles. You shipped them and they were done. The games industry was also often trying to ship quickly. Small teams too. Latest tweaks to memcpy or fine tuning or revisiting the finer points of an already adequate SDK is low priority.

By contrast, many more people are updating optimizations to GCC or clang for arm, more frequently and over a longer timeframe.

Re: C Strings and my slow descent to madness

#199

Post by kens »

It's strange that computer programmers think of themselves as being on the cutting edge of technology, but then we use a language that is over 50 years old. Of course there are going to be lots of problems with C strings since they were designed for a totally different world (no Unicode, no security issues, memory was precious, etc). The hardware is a million times as powerful but the software environment improves at a glacial pace.

Re: C Strings and my slow descent to madness

#200

Post by lolcatuser »

kelnos wrote: post #148
_benj wrote: post #5

With the woes of string.h being known, why not just use an alternative like https://github.com/antirez/sds ? I’ve also been having a blast with C because writing C feels like being a god! But the biggest thing that I like about C is that the world is sort of written on it! Just yesterday I needed to parse a JSON… found a bunch of libraries that do that and just picked one that I liked the API.

> I’ve also been having a blast with C because writing C feels like being a god! That's funny, because I look at it in the opposite way: it makes me feel like a super-fallible human because it's so easy for me to break things in horrible ways, something a hypothetical god would not do. Something like Rust &str or String would make me feel more like a god, as I can do whatever I want (more or less) without worrying ab…

A hypothetical god would not destroy the world, but absolutely could.

I think that's the idea - they're not reveling in the fact that they can do anything anybody could reasonably want to do, they're reveling in the fact that they can also do everything else, too.

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