Thread

1. peterus · 1789747101 · focus · HN ↗

   There are valid use cases for the infinite while(1) loop in microcontroller programming (contrary to popular belief it seems). Autogenerated HAL code for the stm32 uses it for error handlers, and they support C++ so I am surprised this was UB.

   I only use it for error handling and of course it is a bad idea to use this to wait/stall in power sensitive applications, in that case use wake from interrupt.

   As an aside, I like to include a software breakpoint in my error handlers. It makes debugging easier without wasting a hardware breakpoint (which are physically limited by the microcontroller):

     __BKPT();
     while (1)
       ;

   1. rfgplk · 1789750845 · focus · HN ↗

      UB according to the standard committee is "we didn't think of it". It's not literal UB it's well known what it compiles down to, every time. (.loop: jmp .loop)

      1. usefulcat · 1789755104 · focus · HN ↗

         It's not "we didn't think of it", it's literally "the standard has nothing to say about it", which means that any standard-conforming implementation is free to do whatever it wants, meaning that different implementations may handle it differently.

         > It's not literal UB it's well known what it compiles down to, every time. (.loop: jmp .loop)

         That might be true for a particular version of a particular compiler, but if you assume that it's true for all standard-conforming compilers (now and in the future) then you're making an assumption that is not supported by the standard.

      2. aw1621107 · 1789757091 · focus · HN ↗

         > It's not literal UB it's well known what it compiles down to, every time. (.loop: jmp .loop)

         ...Uh, the example shown at the literal top of the blog demonstrates precisely the opposite?

Unofficial Hacker News client; not affiliated with Y Combinator.