Catch-23: The New C Standard Sets the World on Fire

Re:Catch-23: The New C Standard Sets the World on Fire by the_why_of_y on Sunday April 02, 2023 @05:08AM (#35408606)

My complaint here is that it took C more than 30 years between defining signed integer overflow as UB and providing programmers with standard library facilities to check if a signed integer operation would result in overflow.

I much prefer Rust's approach to arithmetic, where overflow with plain arithmetic operators is defined as a bug, and panics on debug-enabled builds, plus special operations in the standard library like wrapping_add and saturating_add for the special cases where overflow is expected.

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Re:Catch-23: The New C Standard Sets the World on Fire by chongli on Sunday April 02, 2023 @06:05AM (#35408957)

My complaint here is that it took C more than 30 years ... I much prefer Rust's approach

That's an odd complaint. Rust didn't spring forth fully formed from the ether, it stands on the shoulders of C (and other giants of PL history). 30 years ago you couldn't use Rust at all because it didn't exist.

The reason the committee doesn't just radically change C in all these nice ways to catch up to Rust is because it would be incompatible. Then you wouldn't have fixed C, you'd just have two languages: "old C", which all of the existing C code in the world is written in, and "new C", which nothing is written in. At that point why not just start over from scratch, like they did with Rust?

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Re:Catch-23: The New C Standard Sets the World on Fire by the_why_of_y on Sunday April 02, 2023 @04:46PM (#35415025)

Interestingly, the first Ada standard in 1983 defined signed integer overflow to raise a CONSTRAINT_ERROR exception.

But apparently it lacked unsigned integers with modular arithmetic?

http://archive.adaic.com/standards/83lrm/html/lrm-11-01.html... http://archive.adaic.com/standards/83lrm/html/lrm-03-05.html

The 2012 version is a bit more readable, and has unsigned integers:

For a signed integer type, the exception Constraint_Error is raised by the execution of an operation that cannot deliver the correct result because it is outside the base range of the type. For any integer type, Constraint_Error is raised by the operators "/", "rem", and "mod" if the right operand is zero.

For a modular type, if the result of the execution of a predefined operator (see 4.5) is outside the base range of the type, the result is reduced modulo the modulus of the type to a value that is within the base range of the type.

http://www.ada-auth.org/standards/rm12_w_tc1/html/RM-3-5-4.h...

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