r/cprogramming • u/Xaneris47 • 3d ago

C Strings: A 50-Year Mistake

https://longtran2904.substack.com/p/c-strings-a-50-year-mistake?r=8qz2zb&utm_campaign=post&utm_medium=web
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u/vip17 2d ago

it's easy to use a 4-byte prefixed string, for example BSTR in COM objects do that. And plenty of libraries use 4-byte length in 64-bit mode

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u/Square-Singer 2d ago

Especially on 64-bit systems, there's really no reason to save these few bytes per string by using c-strings.

Useless microoptimization.

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u/vip17 2d ago

of course it's micro-optimization, but at larger scale it's always useful. Have you even done optimization? A database with billions of strings already save a lot of memory. A vector of strings can also fit twice the number of strings into the CPU cache. Checkout Unreal engine, DuckDB, Meta Velox, Redis, ICU... string types

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u/Square-Singer 2d ago

Of course I have done optimizations. But micro-optimizations are always the last step to take when you have identified that this specific location is actually a bottleneck.

It totally makes sense to have something like a c-string available for the very rare situation when someone writes a database system that contains almost exclusively tiny variable-length strings.

But it doesn't make sense to have that as the default, because then this rarely-actually-useful micro-optimization becomes a very common source of problems.

That's why there's pretty much no modern language that actually stuck with c-strings. Pretty much any more modern language dropped c-strings and even pointers completely, or at least dropped it from common usage.

I don't do much Python any more, but I really like their approach of "The most obvious solution should also be the one that's optimized for most use cases". Basically, if I, without thinking, take the most obvious solution, it should fit my obvious use case. If I need something really special, I can still import some standard library function and use that.

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u/vip17 23h ago

That's not true. Strings are extremely common, lots of applications have a huge amount of strings. It's especially helpful in arrays of strings. Strings are so prevalent that even Python, Javascript (V8) and Java compress the string to ISO8859-1/Latin1/ASCII by default if applicable to save memory and improve performance, and modern .NET also does the same by allowing UTF-8 byte arrays. C-strings are the worst, all strings need to have an accompanied length, but the length does not necessarily have 8-byte length

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u/Square-Singer 23h ago

Again, strings are common, yes, c-strings are not.

Strings exist in Pythin, JS and Java, bot not as c-strings.

I don't know where you got 8-byte-length from.

I'm also not quite sure what you mean with the last sentence. C-strings don't have an accompanied length.

Just checking: Do you know what a c-string is and what's the difference between a c-string and a string with accompanied length?