GetMarkersFromEisenkraut.scala

import osc.Implicits._
val c = osc.UDP.Client(localhost -> 17737)

var marks = Vector.empty[Long]

c.action = {
  case osc.Message("/query.reply", 1, count: Int) =>
    c ! osc.Message("/doc/active/markers", "get", 2, "range", 0, count)
  case osc.Message("/get.reply", 2, info @ _*) =>
    marks = info.sliding(1, 2).flatten.collect {
      case p: Int => p.toLong
    } .toVector
    println(marks.size)
  case other => println(s"Not handled: $other")
}

c.connect()

c ! osc.Message("/doc/active/markers", "query", 1, "count")

marks // result

TCP variant

import osc.Implicits._
val c = osc.TCP.Client("127.0.0.1" -> 17737)

var marks = Vector.empty[Long]

c.action = {
  case osc.Message("/query.reply", 1, count: Int) =>
    c ! osc.Message("/doc/active/markers", "get", 2, "range", 0, count)
  case osc.Message("/get.reply", 2, info @ _*) =>
    marks = info.sliding(1, 2).flatten.collect {
      case p: Int => p.toLong
    } .toVector
    println(marks.size)
  case other => println(s"Not handled: $other")
}

c.connect()

c ! osc.Message("/doc/active/markers", "query", 1, "count")

marks // result

c.close()

markers are now (1.4.2) also printed via Debug > Dump Region Structure.