Chris Wellons

  1. Speculations on arenas and non-trivial destructors

    As I continue to reflect on arenas and lifetimes in C++, I realized that dealing with destructors is not so onerous. In fact, it does not even impact my established arena usage! That is, implicit RAII-style deallocation at scope termination, which works even in plain old C. With a small change we can…

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  2. More speculations on arenas in C++

    Update October 2025: further enhancements. Patrice Roy’s new book, C++ Memory Management, has made me more conscious of object lifetimes. C++ is stricter than C about lifetimes, and common, textbook memory management that’s sound in C is less so in C++ — more than I realized. The book also presents a…

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  3. Hierarchical field sort with string interning

    In a recent, real world problem I needed to load a heterogeneous sequence of records from a buffer. Record layout is defined in a header before the sequence. Each field is numeric, with a unique name composed of non-empty alphanumeric period-delimited segments, where segments signify nested structure…

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  4. Assemblers in w64devkit, and other updates

    Today I’m releasing w64devkit 2.4.0, mostly for GCC 15.2. As usual, it includes the continuous background improvements, and ideally each release is the best so far. The first release included the Netwide Assembler, NASM, but it’s now been a year since I removed NASM from the distribution (2.0.0). I’m…

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  5. Parameterized types in C using the new tag compatibility rule

    C23 has a new rule for struct, union, and enum compatibility finally appearing in compilers starting with GCC 15, released this past April, and Clang later this year. The same struct defined in different translation units (TU) has always been compatible — essential to how they work. Until this rule change…

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  6. WebAssembly: How to allocate your allocator

    An early, small hurdle diving into WebAssembly was allocating my allocator. On a server or desktop with virtual memory, the allocator asks the operating system to map fresh pages into its address space (sbrk, anonymous mmap, VirtualAlloc), which it then dynamically allocates to different purposes. In…

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  7. Lessons learned from my first dive into WebAssembly

    It began as a water sort puzzle solver, constructed similarly to my British Square solver. It was nearly playable, so I added a user interface with SDL2. My wife enjoyed it on her desktop, but wished to play on her phone. So then I needed to either rewrite it in JavaScript and hope the solver was still…

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  8. A more robust raw OpenBSD syscall demo

    Ted Unangst published dude, where are your syscalls? on flak yesterday, with a neat demonstration of OpenBSD’s pinsyscall security feature, whereby only pre-registered addresses are allowed to make system calls. Whether it strengthens or weakens security is up for debate, but regardless it’s an interesting…

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