proc addBytes[T](buf: seq[uint8], a: T)

[timotheecour]

when true:
  import std/[sugar,locks]
  proc addBytes[T](buf: var seq[uint8], a: T) =
    let n = T.sizeof
    let old = buf.len
    buf.setLen old + n
    copyMem(buf[old].addr, a.unsafeAddr, n)

  var a: Lock
  assert a.sizeof == 64
  initLock(a)

  echo seq[uint8].default.dup(addBytes(a)) # @[90, 84, 85, 77, 0...]

originally proposed in nim-lang#17944 (comment) (but changed its semantics to be additive, which is strictly more flexible)

note

maybe add to std/reflection nim-lang#17641

[juancarlospaco]

buf: var openArray[uint8] ?. 🤔

[timotheecour]

can't work with setLen

[juancarlospaco]

Iam wrong, you are right.