The C programming language is designed to let programmers work at both low and high levels. In particular, for applications like operating system development, cryptography, numerical methods, and network processing, programmers can go back and forth between treating data as
The developers of Google’s Spanner database built an interesting system but chose to build their own clock synchronization technology instead of getting a more precise off the shelf solution and chose to make extensive use of the notoriously complex Paxos
From 1991, Barbara Liskov looked at the implications for distributed computing when synchronized clocks are available.
Note: these were sent to WG14 as official proposals. See also a longer paper, something on alias and Torvalds remarks and Regehr’s paper. 6.12 Proposal to clarify undefined behavior range for implementations [N 2278] 6.13 Proposal to make aliasing consistent [N
One of the common defenses of the abuse of “undefined behavior” by C compilers, and the stupid aliasing rules in the standard is that those things are necessary for optimizations, like using vector operations. Here’s an example of where gcc
See also PLOS article, pointer alias in C and remarks on the purpose of C. From: LKML From Linus Torvalds <> Date Tue, 5 Jun 2018 10:30:21 -0700 Subject Re: [GIT PULL] Device properties framework update for v4.18-rc1 On Mon, Jun
Perhaps there is some reason to provide a mechanism for asserting, in a particular patch of code, that the compiler is free to make optimistic assumptions about the kinds of aliasing that can occur. I don’t know any acceptable way of
C STANDARD UNDEFINED BEHAVIOR VERSUS WITTGENSTEIN 1. DEPRESSING AND FAINTLY TERRIFYING Chris Lattner, the architect of the Clang/LLVM C compiler explained the effects of the C standard’s “undefined behavior (UB): UB is an inseperable part of C programming, […] this
Via @johnregehr this further tale of compiler “optimizations” that break correct C code without even a warning by deleting a necessary null pointer check. In this example, Bar contains a stack of Foos. Sometimes the Foo stack is empty, so
Distributed computation involves many interesting issues concerning shared data. Here I want to sketch out what networks look like using applied (informal) mathematics so we can look at some algorithms for consensus and data consistency. No formal methods or category