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0 pointsthe_why_of_y2y ago0 comments

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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chongli2y ago

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?

the_why_of_yOP2y ago

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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