What is a pre-memory read in C++?

Question

An article I saw today talks about the Rust programming language (being developed by Mozilla) and how it intends to replace C++. One of the cited benefits of Rust is the lack of pre-memory reads. Quoting Mozilla CTO Brendan Eich...

"There's no pre-memory reads" in Rust, he said, but there are in C++. Those problems "lead to a lot of browser vulnerabilities" and would be solved by Rust.

Interestingly, there are only 4 hits on Google right now for the phrase "pre-memory reads", all of which refer to the article itself. What is a pre-memory read in C++ and why is it bad?

Answer 1

There appears to have been a correction to the article. The corrected quote is as follows:

He noted that every year browsers fall victim to hacking in the annual Pwn2Own contest at the CanSecWest conference. "There's no free memory reads" in Rust, he said, but there are in C++. Those problems "lead to a lot of browser vulnerabilities" and would be solved by Rust, which is a self-compiling language.

I think this explains it.

Answer 2

That article also contains this quote, which is clearly wrong:

C++ is unsafe by design," he said. "It gets you down to the metal," a term that means that the code runs natively and doesn't have to be compiled before the CPU can understand it, "but it is unsafe.

So, I think it's safe to say that article is unreliable, and has possibly mis-quoted him.