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0 pointslelanthran2y ago0 comments

> A library isn't the language that is described by the ISO C standard document.

Sure, but the poster didn't ask "what comes with apl and oberon that doesn't come with C", they asked "what do you think apl and oberon can express that C cannot?"

And you absolutely, positively can EXPRESS bounds checking in C. I'm not sure where you heard that this is impossible, but it's probable you misunderstood or that source is wrong.

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4 comments · 2 top-level

pjmlp2y ago· 2 in thread

First of all your library doesn't come with C, otherwise it would be defined on the PDF I can buy from ISO.

Secondly using if statements and conditional expressions isn't what bounds checking in a programing language is about.

Here is some education material,

https://en.wikipedia.org/wiki/Bounds_checking

> Many programming languages, such as C, never perform automatic bounds checking to raise speed. However, this leaves many off-by-one errors and buffer overflows uncaught. Many programmers believe these languages sacrifice too much for rapid execution.[1] In his 1980 Turing Award lecture, C. A. R. Hoare described his experience in the design of ALGOL 60, a language that included bounds checking, saying:

Feel free to update the Wikipedia page and convince Wikipedia of your reasoning.

lelanthranOP2y ago

What does any of that have to do with whether or not you can EXPRESS bounds checking in a C program?

You were misinformed; one can certainly express bounds checking in a C program, independent of libraries or compiler extensions.

pjmlp2y ago

Please educate us, we are all curious to learn how.

Only the ISO C language is allowed, declare C array and then show us how do you validate the accesses with the index operator.

As second exercise, show us how a function call using pointer + length, validates that the lengh into the pointer region is a valid length for the memory region total size.

2 more replies

agumonkey2y ago

Hmm good question, but i think my question is located half way. What you describe is basically turing completeness, C allow to write more on top, but it won't be integrated in the base constructs of the language. I admit that this comment too is fuzzy :)

I hope things don't go angry in here

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