Merge branch 'devel' of github.com:nim-lang/Nim into devel

2025-12-29 09:24:36 +00:00 · 2016-07-06 16:48:14 +02:00
parent e73fd64f38 46237a273d
commit 17d97462cf
25 changed files with 3914 additions and 1574 deletions
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@@ -610,7 +610,7 @@ type
    mEqIdent, mEqNimrodNode, mSameNodeType, mGetImpl,
    mNHint, mNWarning, mNError,
    mInstantiationInfo, mGetTypeInfo, mNGenSym,
-    mNimvm
+    mNimvm, mIntDefine, mStrDefine

 # things that we can evaluate safely at compile time, even if not asked for it:
 const
--- a/compiler/ccgcalls.nim
+++ b/compiler/ccgcalls.nim
@@ -260,7 +260,11 @@ proc genOtherArg(p: BProc; ri: PNode; i: int; typ: PType): Rope =
    else:
      result = genArgNoParam(p, ri.sons[i]) #, typ.n.sons[i].sym)
  else:
-    result = genArgNoParam(p, ri.sons[i])
+    if tfVarargs notin typ.flags:
+      localError(ri.info, "wrong argument count")
+      result = nil
+    else:
+      result = genArgNoParam(p, ri.sons[i])

 discard """
 Dot call syntax in C++
--- a/compiler/commands.nim
+++ b/compiler/commands.nim
@@ -342,7 +342,11 @@ proc processSwitch(switch, arg: string, pass: TCmdLinePass, info: TLineInfo) =
    discard "allow for backwards compatibility, but don't do anything"
  of "define", "d":
    expectArg(switch, arg, pass, info)
-    defineSymbol(arg)
+    if {':', '='} in arg:
+      splitSwitch(arg, key, val, pass, info)
+      defineSymbol(key, val)
+    else:
+      defineSymbol(arg)
  of "undef", "u":
    expectArg(switch, arg, pass, info)
    undefSymbol(arg)
--- a/compiler/condsyms.nim
+++ b/compiler/condsyms.nim
@@ -19,8 +19,8 @@ var gSymbols: StringTableRef
 const
  catNone = "false"

-proc defineSymbol*(symbol: string) =
-  gSymbols[symbol] = "true"
+proc defineSymbol*(symbol: string, value: string = "true") =
+  gSymbols[symbol] = value

 proc undefSymbol*(symbol: string) =
  gSymbols[symbol] = catNone
@@ -62,6 +62,11 @@ proc isDefined*(symbol: string): bool =

 proc isDefined*(symbol: PIdent): bool = isDefined(symbol.s)

+proc lookupSymbol*(symbol: string): string =
+  result = if isDefined(symbol): gSymbols[symbol] else: nil
+
+proc lookupSymbol*(symbol: PIdent): string = lookupSymbol(symbol.s)
+
 iterator definedSymbolNames*: string =
  for key, val in pairs(gSymbols):
    if val != catNone: yield key
--- a/compiler/jsgen.nim
+++ b/compiler/jsgen.nim
@@ -1557,8 +1557,16 @@ proc genRepr(p: PProc, n: PNode, r: var TCompRes) =
  of tyEnum, tyOrdinal:
    gen(p, n.sons[1], r)
    useMagic(p, "cstrToNimstr")
+    var offset = ""
+    if t.kind == tyEnum:
+      let firstFieldOffset = t.n.sons[0].sym.position
+      if firstFieldOffset < 0:
+        offset = "+" & $(-firstFieldOffset)
+      elif firstFieldOffset > 0:
+        offset = "-" & $firstFieldOffset
+
    r.kind = resExpr
-    r.res = "cstrToNimstr($1.node.sons[$2].name)" % [genTypeInfo(p, t), r.res]
+    r.res = "cstrToNimstr($1.node.sons[$2$3].name)" % [genTypeInfo(p, t), r.res, rope(offset)]
  else:
    # XXX:
    internalError(n.info, "genRepr: Not implemented")
--- a/compiler/pragmas.nim
+++ b/compiler/pragmas.nim
@@ -63,7 +63,8 @@ const
    wImportCpp, wImportObjC, wError, wNoInit, wCompileTime, wGlobal,
    wGensym, wInject, wCodegenDecl, wGuard, wGoto, wExportNims}
  constPragmas* = {wImportc, wExportc, wHeader, wDeprecated, wMagic, wNodecl,
-    wExtern, wImportCpp, wImportObjC, wError, wGensym, wInject, wExportNims}
+    wExtern, wImportCpp, wImportObjC, wError, wGensym, wInject, wExportNims,
+    wIntDefine, wStrDefine}
  letPragmas* = varPragmas
  procTypePragmas* = {FirstCallConv..LastCallConv, wVarargs, wNosideeffect,
                      wThread, wRaises, wLocks, wTags, wGcSafe}
@@ -898,6 +899,10 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: int,
      of wBase:
        noVal(it)
        sym.flags.incl sfBase
+      of wIntDefine:
+        sym.magic = mIntDefine
+      of wStrDefine:
+        sym.magic = mStrDefine
      else: invalidPragma(it)
    else: invalidPragma(it)

--- a/compiler/semfold.nim
+++ b/compiler/semfold.nim
@@ -640,6 +640,12 @@ proc getConstExpr(m: PSym, n: PNode): PNode =
      of mNaN: result = newFloatNodeT(NaN, n)
      of mInf: result = newFloatNodeT(Inf, n)
      of mNegInf: result = newFloatNodeT(NegInf, n)
+      of mIntDefine:
+        if isDefined(s.name):
+          result = newIntNodeT(lookupSymbol(s.name).parseInt, n)
+      of mStrDefine:
+        if isDefined(s.name):
+          result = newStrNodeT(lookupSymbol(s.name), n)
      else:
        if sfFakeConst notin s.flags: result = copyTree(s.ast)
    of {skProc, skMethod}:
--- a/compiler/types.nim
+++ b/compiler/types.nim
@@ -727,6 +727,7 @@ proc equalParam(a, b: PSym): TParamsEquality =
    result = paramsNotEqual

 proc sameConstraints(a, b: PNode): bool =
+  if isNil(a) and isNil(b): return true
  internalAssert a.len == b.len
  for i in 1 .. <a.len:
    if not exprStructuralEquivalent(a[i].sym.constraint,
--- a/compiler/vmgen.nim
+++ b/compiler/vmgen.nim
@@ -516,8 +516,11 @@ proc genCall(c: PCtx; n: PNode; dest: var TDest) =
  if dest < 0 and not isEmptyType(n.typ): dest = getTemp(c, n.typ)
  let x = c.getTempRange(n.len, slotTempUnknown)
  # varargs need 'opcSetType' for the FFI support:
-  let fntyp = n.sons[0].typ
+  let fntyp = skipTypes(n.sons[0].typ, abstractInst)
  for i in 0.. <n.len:
+    if i > 0 and i < sonsLen(fntyp):
+      let paramType = fntyp.n.sons[i]
+      if paramType.typ.isCompileTimeOnly: continue
    var r: TRegister = x+i
    c.gen(n.sons[i], r)
    if i >= fntyp.len:
--- a/compiler/wordrecg.nim
+++ b/compiler/wordrecg.nim
@@ -36,6 +36,7 @@ type
    wColon, wColonColon, wEquals, wDot, wDotDot,
    wStar, wMinus,
    wMagic, wThread, wFinal, wProfiler, wObjChecks,
+    wIntDefine, wStrDefine,

    wDestroy,

@@ -121,7 +122,7 @@ const

    ":", "::", "=", ".", "..",
    "*", "-",
-    "magic", "thread", "final", "profiler", "objchecks",
+    "magic", "thread", "final", "profiler", "objchecks", "intdefine", "strdefine",

    "destroy",

--- a/doc/basicopt.txt
+++ b/doc/basicopt.txt
@@ -11,7 +11,9 @@ Arguments:
  arguments are passed to the program being run (if --run option is selected)
 Options:
  -p, --path:PATH           add path to search paths
-  -d, --define:SYMBOL       define a conditional symbol
+  -d, --define:SYMBOL(:VAL)
+                            define a conditional symbol
+                            (Optionally: Define the value for that symbol)
  -u, --undef:SYMBOL        undefine a conditional symbol
  -f, --forceBuild          force rebuilding of all modules
  --stackTrace:on|off       turn stack tracing on|off
--- a/doc/manual/pragmas.txt
+++ b/doc/manual/pragmas.txt
@@ -1011,3 +1011,30 @@ debugging:

  # ... complex code here that produces crashes ...

+compile time define pragmas
+---------------------------
+
+The pragmas listed here can be used to optionally accept values from
+the -d/--define option at compile time.
+
+The implementation currently provides the following possible options (various
+others may be added later).
+
+===============  ============================================
+pragma           description
+===============  ============================================
+intdefine        Reads in a build-time define as an integer
+strdefine        Reads in a build-time define as a string
+===============  ============================================
+
+.. code-block:: nim
+   const FooBar {.intdefine.}: int = 5
+   echo FooBar
+
+.. code-block:: bash
+   nim c -d:FooBar=42 foobar.c
+
+In the above example, providing the -d flag causes the symbol
+``FooBar`` to be overwritten at compile time, printing out 42. If the
+``-d:FooBar=42`` were to be omitted, the default value of 5 would be
+used.
--- a/doc/nimc.rst
+++ b/doc/nimc.rst
@@ -98,6 +98,11 @@ enable builds in release mode (``-d:release``) where certain safety checks are
 omitted for better performance. Another common use is the ``-d:ssl`` switch to
 activate `SSL sockets <sockets.html>`_.

+Additionally, you may pass a value along with the symbol: ``-d:x=y``
+which may be used in conjunction with the `compile time define
+pragmas<manual.html#implementation-specific-pragmas-compile-time-define-pragmas>`_
+to override symbols during build time.
+

 Configuration files
 -------------------
@@ -370,7 +375,10 @@ For example, to generate code for an `AVR`:idx: processor use this command::
 For the ``standalone`` target one needs to provide
 a file ``panicoverride.nim``.
 See ``tests/manyloc/standalone/panicoverride.nim`` for an example
-implementation.
+implementation.  Additionally, users should specify the
+amount of heap space to use with the ``-d:StandaloneHeapSize=<size>``
+command line switch.  Note that the total heap size will be
+``<size> * sizeof(float64)``.


 Nim for realtime systems
--- a/lib/pure/collections/sets.nim
+++ b/lib/pure/collections/sets.nim
@@ -58,7 +58,7 @@ proc isValid*[A](s: HashSet[A]): bool =
  ## initialized. Example:
  ##
  ## .. code-block ::
-  ##   proc savePreferences(options: Set[string]) =
+  ##   proc savePreferences(options: HashSet[string]) =
  ##     assert options.isValid, "Pass an initialized set!"
  ##     # Do stuff here, may crash in release builds!
  result = not s.data.isNil
@@ -72,7 +72,7 @@ proc len*[A](s: HashSet[A]): int =
  ##
  ## .. code-block::
  ##
-  ##   var values: Set[int]
+  ##   var values: HashSet[int]
  ##   assert(not values.isValid)
  ##   assert values.len == 0
  result = s.counter
@@ -338,7 +338,7 @@ proc init*[A](s: var HashSet[A], initialSize=64) =
  ## existing values and calling `excl() <#excl,TSet[A],A>`_ on them. Example:
  ##
  ## .. code-block ::
-  ##   var a: Set[int]
+  ##   var a: HashSet[int]
  ##   a.init(4)
  ##   a.incl(2)
  ##   a.init
--- a/lib/pure/ioselectors.nim
+++ b/lib/pure/ioselectors.nim
--- a/lib/pure/ioselects/ioselectors_epoll.nim
+++ b/lib/pure/ioselects/ioselectors_epoll.nim
@@ -0,0 +1,461 @@
+#
+#
+#            Nim's Runtime Library
+#        (c) Copyright 2016 Eugene Kabanov
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+# This module implements Linux epoll().
+
+import posix, times
+
+# Maximum number of events that can be returned
+const MAX_EPOLL_RESULT_EVENTS = 64
+
+type
+  SignalFdInfo* {.importc: "struct signalfd_siginfo",
+                  header: "<sys/signalfd.h>", pure, final.} = object
+    ssi_signo*: uint32
+    ssi_errno*: int32
+    ssi_code*: int32
+    ssi_pid*: uint32
+    ssi_uid*: uint32
+    ssi_fd*: int32
+    ssi_tid*: uint32
+    ssi_band*: uint32
+    ssi_overrun*: uint32
+    ssi_trapno*: uint32
+    ssi_status*: int32
+    ssi_int*: int32
+    ssi_ptr*: uint64
+    ssi_utime*: uint64
+    ssi_stime*: uint64
+    ssi_addr*: uint64
+    pad* {.importc: "__pad".}: array[0..47, uint8]
+
+  eventFdData {.importc: "eventfd_t",
+                header: "<sys/eventfd.h>", pure, final.} = uint64
+  epoll_data {.importc: "union epoll_data", header: "<sys/epoll.h>",
+               pure, final.} = object
+    u64 {.importc: "u64".}: uint64
+  epoll_event {.importc: "struct epoll_event",
+                header: "<sys/epoll.h>", pure, final.} = object
+    events: uint32 # Epoll events
+    data: epoll_data # User data variable
+
+const
+  EPOLL_CTL_ADD = 1          # Add a file descriptor to the interface.
+  EPOLL_CTL_DEL = 2          # Remove a file descriptor from the interface.
+  EPOLL_CTL_MOD = 3          # Change file descriptor epoll_event structure.
+  EPOLLIN = 0x00000001
+  EPOLLOUT = 0x00000004
+  EPOLLERR = 0x00000008
+  EPOLLHUP = 0x00000010
+  EPOLLRDHUP = 0x00002000
+  EPOLLONESHOT = 1 shl 30
+
+proc epoll_create(size: cint): cint
+     {.importc: "epoll_create", header: "<sys/epoll.h>".}
+proc epoll_ctl(epfd: cint; op: cint; fd: cint; event: ptr epoll_event): cint
+     {.importc: "epoll_ctl", header: "<sys/epoll.h>".}
+proc epoll_wait(epfd: cint; events: ptr epoll_event; maxevents: cint;
+                 timeout: cint): cint
+     {.importc: "epoll_wait", header: "<sys/epoll.h>".}
+proc timerfd_create(clock_id: ClockId, flags: cint): cint
+     {.cdecl, importc: "timerfd_create", header: "<sys/timerfd.h>".}
+proc timerfd_settime(ufd: cint, flags: cint,
+                      utmr: var Itimerspec, otmr: var Itimerspec): cint
+     {.cdecl, importc: "timerfd_settime", header: "<sys/timerfd.h>".}
+proc signalfd(fd: cint, mask: var Sigset, flags: cint): cint
+     {.cdecl, importc: "signalfd", header: "<sys/signalfd.h>".}
+proc eventfd(count: cuint, flags: cint): cint
+     {.cdecl, importc: "eventfd", header: "<sys/eventfd.h>".}
+proc ulimit(cmd: cint): clong
+     {.importc: "ulimit", header: "<ulimit.h>", varargs.}
+
+when hasThreadSupport:
+  type
+    SelectorImpl[T] = object
+      epollFD : cint
+      maxFD : int
+      fds: ptr SharedArray[SelectorKey[T]]
+      count: int
+    Selector*[T] = ptr SelectorImpl[T]
+else:
+  type
+    SelectorImpl[T] = object
+      epollFD : cint
+      maxFD : int
+      fds: seq[SelectorKey[T]]
+      count: int
+    Selector*[T] = ref SelectorImpl[T]
+type
+  SelectEventImpl = object
+    efd: cint
+  SelectEvent* = ptr SelectEventImpl
+
+proc newSelector*[T](): Selector[T] =
+  var maxFD = int(ulimit(4, 0))
+  doAssert(maxFD > 0)
+
+  var epollFD = epoll_create(MAX_EPOLL_RESULT_EVENTS)
+  if epollFD < 0:
+    raiseOsError(osLastError())
+
+  when hasThreadSupport:
+    result = cast[Selector[T]](allocShared0(sizeof(SelectorImpl[T])))
+    result.epollFD = epollFD
+    result.maxFD = maxFD
+    result.fds = allocSharedArray[SelectorKey[T]](maxFD)
+  else:
+    result = Selector[T]()
+    result.epollFD = epollFD
+    result.maxFD = maxFD
+    result.fds = newSeq[SelectorKey[T]](maxFD)
+
+proc close*[T](s: Selector[T]) =
+  if posix.close(s.epollFD) != 0:
+    raiseOSError(osLastError())
+  when hasThreadSupport:
+    deallocSharedArray(s.fds)
+    deallocShared(cast[pointer](s))
+
+proc newSelectEvent*(): SelectEvent =
+  let fdci = eventfd(0, 0)
+  if fdci == -1:
+    raiseOSError(osLastError())
+  setNonBlocking(fdci)
+  result = cast[SelectEvent](allocShared0(sizeof(SelectEventImpl)))
+  result.efd = fdci
+
+proc setEvent*(ev: SelectEvent) =
+  var data : uint64 = 1
+  if posix.write(ev.efd, addr data, sizeof(uint64)) == -1:
+    raiseOSError(osLastError())
+
+proc close*(ev: SelectEvent) =
+  discard posix.close(ev.efd)
+  deallocShared(cast[pointer](ev))
+
+template checkFd(s, f) =
+  if f >= s.maxFD:
+    raise newException(ValueError, "Maximum file descriptors exceeded")
+
+proc registerHandle*[T](s: Selector[T], fd: SocketHandle,
+                        events: set[Event], data: T) =
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+  s.setKey(fdi, fdi, events, 0, data)
+  if events != {}:
+    var epv = epoll_event(events: EPOLLRDHUP)
+    epv.data.u64 = fdi.uint
+    if Event.Read in events: epv.events = epv.events or EPOLLIN
+    if Event.Write in events: epv.events = epv.events or EPOLLOUT
+    if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fdi.cint, addr epv) == -1:
+      raiseOSError(osLastError())
+    inc(s.count)
+
+proc updateHandle*[T](s: Selector[T], fd: SocketHandle, events: set[Event]) =
+  let maskEvents = {Event.Timer, Event.Signal, Event.Process, Event.Vnode,
+                    Event.User, Event.Oneshot, Event.Error}
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+  doAssert(pkey.events * maskEvents == {})
+  if pkey.events != events:
+    var epv = epoll_event(events: EPOLLRDHUP)
+    epv.data.u64 = fdi.uint
+
+    if Event.Read in events: epv.events = epv.events or EPOLLIN
+    if Event.Write in events: epv.events = epv.events or EPOLLOUT
+
+    if pkey.events == {}:
+      if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fdi.cint, addr epv) == -1:
+        raiseOSError(osLastError())
+      inc(s.count)
+    else:
+      if events != {}:
+        if epoll_ctl(s.epollFD, EPOLL_CTL_MOD, fdi.cint, addr epv) == -1:
+          raiseOSError(osLastError())
+      else:
+        if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fdi.cint, addr epv) == -1:
+          raiseOSError(osLastError())
+        dec(s.count)
+    pkey.events = events
+
+proc unregister*[T](s: Selector[T], fd: int|SocketHandle) =
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+
+  if pkey.events != {}:
+    if pkey.events * {Event.Read, Event.Write} != {}:
+      var epv = epoll_event()
+      if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fdi.cint, addr epv) == -1:
+        raiseOSError(osLastError())
+      dec(s.count)
+    elif Event.Timer in pkey.events:
+      var epv = epoll_event()
+      if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fdi.cint, addr epv) == -1:
+        raiseOSError(osLastError())
+      discard posix.close(fdi.cint)
+      dec(s.count)
+    elif Event.Signal in pkey.events:
+      var epv = epoll_event()
+      if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fdi.cint, addr epv) == -1:
+        raiseOSError(osLastError())
+      var nmask, omask: Sigset
+      discard sigemptyset(nmask)
+      discard sigemptyset(omask)
+      discard sigaddset(nmask, cint(s.fds[fdi].param))
+      unblockSignals(nmask, omask)
+      discard posix.close(fdi.cint)
+      dec(s.count)
+    elif Event.Process in pkey.events:
+      var epv = epoll_event()
+      if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fdi.cint, addr epv) == -1:
+        raiseOSError(osLastError())
+      var nmask, omask: Sigset
+      discard sigemptyset(nmask)
+      discard sigemptyset(omask)
+      discard sigaddset(nmask, SIGCHLD)
+      unblockSignals(nmask, omask)
+      discard posix.close(fdi.cint)
+      dec(s.count)
+  pkey.ident = 0
+  pkey.events = {}
+
+proc unregister*[T](s: Selector[T], ev: SelectEvent) =
+  let fdi = int(ev.efd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+  doAssert(Event.User in pkey.events)
+  pkey.ident = 0
+  pkey.events = {}
+  var epv = epoll_event()
+  if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fdi.cint, addr epv) == -1:
+    raiseOSError(osLastError())
+  dec(s.count)
+
+proc registerTimer*[T](s: Selector[T], timeout: int, oneshot: bool,
+                       data: T): int {.discardable.} =
+  var
+    new_ts: Itimerspec
+    old_ts: Itimerspec
+  let fdi = timerfd_create(CLOCK_MONOTONIC, 0).int
+  if fdi == -1:
+    raiseOSError(osLastError())
+  setNonBlocking(fdi.cint)
+
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+
+  var events = {Event.Timer}
+  var epv = epoll_event(events: EPOLLIN or EPOLLRDHUP)
+  epv.data.u64 = fdi.uint
+  if oneshot:
+    new_ts.it_interval.tv_sec = 0.Time
+    new_ts.it_interval.tv_nsec = 0
+    new_ts.it_value.tv_sec = (timeout div 1_000).Time
+    new_ts.it_value.tv_nsec = (timeout %% 1_000) * 1_000_000
+    incl(events, Event.Oneshot)
+    epv.events = epv.events or EPOLLONESHOT
+  else:
+    new_ts.it_interval.tv_sec = (timeout div 1000).Time
+    new_ts.it_interval.tv_nsec = (timeout %% 1_000) * 1_000_000
+    new_ts.it_value.tv_sec = new_ts.it_interval.tv_sec
+    new_ts.it_value.tv_nsec = new_ts.it_interval.tv_nsec
+
+  if timerfd_settime(fdi.cint, cint(0), new_ts, old_ts) == -1:
+    raiseOSError(osLastError())
+  if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fdi.cint, addr epv) == -1:
+    raiseOSError(osLastError())
+  s.setKey(fdi, fdi, events, 0, data)
+  inc(s.count)
+  result = fdi
+
+proc registerSignal*[T](s: Selector[T], signal: int,
+                        data: T): int {.discardable.} =
+  var
+    nmask: Sigset
+    omask: Sigset
+
+  discard sigemptyset(nmask)
+  discard sigemptyset(omask)
+  discard sigaddset(nmask, cint(signal))
+  blockSignals(nmask, omask)
+
+  let fdi = signalfd(-1, nmask, 0).int
+  if fdi == -1:
+    raiseOSError(osLastError())
+  setNonBlocking(fdi.cint)
+
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+
+  var epv = epoll_event(events: EPOLLIN or EPOLLRDHUP)
+  epv.data.u64 = fdi.uint
+  if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fdi.cint, addr epv) == -1:
+    raiseOSError(osLastError())
+  s.setKey(fdi, signal, {Event.Signal}, signal, data)
+  inc(s.count)
+  result = fdi
+
+proc registerProcess*[T](s: Selector, pid: int,
+                         data: T): int {.discardable.} =
+  var
+    nmask: Sigset
+    omask: Sigset
+
+  discard sigemptyset(nmask)
+  discard sigemptyset(omask)
+  discard sigaddset(nmask, posix.SIGCHLD)
+  blockSignals(nmask, omask)
+
+  let fdi = signalfd(-1, nmask, 0).int
+  if fdi == -1:
+    raiseOSError(osLastError())
+  setNonBlocking(fdi.cint)
+
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+
+  var epv = epoll_event(events: EPOLLIN or EPOLLRDHUP)
+  epv.data.u64 = fdi.uint
+  epv.events = EPOLLIN or EPOLLRDHUP
+  if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fdi.cint, addr epv) == -1:
+    raiseOSError(osLastError())
+  s.setKey(fdi, pid, {Event.Process, Event.Oneshot}, pid, data)
+  inc(s.count)
+  result = fdi
+
+proc registerEvent*[T](s: Selector[T], ev: SelectEvent, data: T) =
+  let fdi = int(ev.efd)
+  doAssert(s.fds[fdi].ident == 0)
+  s.setKey(fdi, fdi, {Event.User}, 0, data)
+  var epv = epoll_event(events: EPOLLIN or EPOLLRDHUP)
+  epv.data.u64 = ev.efd.uint
+  if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, ev.efd, addr epv) == -1:
+    raiseOSError(osLastError())
+  inc(s.count)
+
+proc flush*[T](s: Selector[T]) =
+  discard
+
+proc selectInto*[T](s: Selector[T], timeout: int,
+                    results: var openarray[ReadyKey[T]]): int =
+  var
+    resTable: array[MAX_EPOLL_RESULT_EVENTS, epoll_event]
+    maxres = MAX_EPOLL_RESULT_EVENTS
+    events: set[Event] = {}
+    i, k: int
+
+  if maxres > len(results):
+    maxres = len(results)
+
+  let count = epoll_wait(s.epollFD, addr(resTable[0]), maxres.cint,
+                         timeout.cint)
+  if count < 0:
+    result = 0
+    let err = osLastError()
+    if cint(err) != EINTR:
+      raiseOSError(err)
+  elif count == 0:
+    result = 0
+  else:
+    i = 0
+    k = 0
+    while i < count:
+      let fdi = int(resTable[i].data.u64)
+      let pevents = resTable[i].events
+      var skey = addr(s.fds[fdi])
+      doAssert(skey.ident != 0)
+      events = {}
+
+      if (pevents and EPOLLERR) != 0 or (pevents and EPOLLHUP) != 0:
+        events.incl(Event.Error)
+      if (pevents and EPOLLOUT) != 0:
+        events.incl(Event.Write)
+      if (pevents and EPOLLIN) != 0:
+        if Event.Read in skey.events:
+          events.incl(Event.Read)
+        elif Event.Timer in skey.events:
+          var data: uint64 = 0
+          if posix.read(fdi.cint, addr data, sizeof(uint64)) != sizeof(uint64):
+            raiseOSError(osLastError())
+          events = {Event.Timer}
+        elif Event.Signal in skey.events:
+          var data = SignalFdInfo()
+          if posix.read(fdi.cint, addr data,
+                        sizeof(SignalFdInfo)) != sizeof(SignalFdInfo):
+            raiseOsError(osLastError())
+          events = {Event.Signal}
+        elif Event.Process in skey.events:
+          var data = SignalFdInfo()
+          if posix.read(fdi.cint, addr data,
+                        sizeof(SignalFdInfo)) != sizeof(SignalFdInfo):
+            raiseOsError(osLastError())
+          if cast[int](data.ssi_pid) == skey.param:
+            events = {Event.Process}
+          else:
+            inc(i)
+            continue
+        elif Event.User in skey.events:
+          var data: uint = 0
+          if posix.read(fdi.cint, addr data, sizeof(uint)) != sizeof(uint):
+            let err = osLastError()
+            if err == OSErrorCode(EAGAIN):
+              inc(i)
+              continue
+            else:
+              raiseOSError(err)
+          events = {Event.User}
+
+      skey.key.events = events
+      results[k] = skey.key
+      inc(k)
+
+      if Event.Oneshot in skey.events:
+        var epv = epoll_event()
+        if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fdi.cint, addr epv) == -1:
+          raiseOSError(osLastError())
+        discard posix.close(fdi.cint)
+        skey.ident = 0
+        skey.events = {}
+        dec(s.count)
+      inc(i)
+    result = k
+
+proc select*[T](s: Selector[T], timeout: int): seq[ReadyKey[T]] =
+  result = newSeq[ReadyKey[T]](MAX_EPOLL_RESULT_EVENTS)
+  let count = selectInto(s, timeout, result)
+  result.setLen(count)
+
+template isEmpty*[T](s: Selector[T]): bool =
+  (s.count == 0)
+
+template withData*[T](s: Selector[T], fd: SocketHandle, value,
+                        body: untyped) =
+  mixin checkFd
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  if s.fds[fdi].ident != 0:
+    var value = addr(s.fds[fdi].key.data)
+    body
+
+template withData*[T](s: Selector[T], fd: SocketHandle, value, body1,
+                        body2: untyped) =
+  mixin checkFd
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  if s.fds[fdi].ident != 0:
+    var value = addr(s.fds[fdi].key.data)
+    body1
+  else:
+    body2
--- a/lib/pure/ioselects/ioselectors_kqueue.nim
+++ b/lib/pure/ioselects/ioselectors_kqueue.nim
@@ -0,0 +1,439 @@
+#
+#
+#            Nim's Runtime Library
+#        (c) Copyright 2016 Eugene Kabanov
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+#  This module implements BSD kqueue().
+
+import posix, times, kqueue
+
+const
+  # Maximum number of cached changes.
+  MAX_KQUEUE_CHANGE_EVENTS = 64
+  # Maximum number of events that can be returned.
+  MAX_KQUEUE_RESULT_EVENTS = 64
+
+when defined(macosx) or defined(freebsd):
+  when defined(macosx):
+    const MAX_DESCRIPTORS_ID = 29 # KERN_MAXFILESPERPROC (MacOS)
+  else:
+    const MAX_DESCRIPTORS_ID = 27 # KERN_MAXFILESPERPROC (FreeBSD)
+  proc sysctl(name: ptr cint, namelen: cuint, oldp: pointer, oldplen: ptr int,
+              newp: pointer, newplen: int): cint
+       {.importc: "sysctl",header: """#include <sys/types.h>
+                                      #include <sys/sysctl.h>"""}
+elif defined(netbsd) or defined(openbsd):
+  # OpenBSD and NetBSD don't have KERN_MAXFILESPERPROC, so we are using
+  # KERN_MAXFILES, because KERN_MAXFILES is always bigger,
+  # than KERN_MAXFILESPERPROC.
+  const MAX_DESCRIPTORS_ID = 7 # KERN_MAXFILES
+  proc sysctl(name: ptr cint, namelen: cuint, oldp: pointer, oldplen: ptr int,
+              newp: pointer, newplen: int): cint
+       {.importc: "sysctl",header: """#include <sys/param.h>
+                                      #include <sys/sysctl.h>"""}
+
+when hasThreadSupport:
+  type
+    SelectorImpl[T] = object
+      kqFD : cint
+      maxFD : int
+      changesTable: array[MAX_KQUEUE_CHANGE_EVENTS, KEvent]
+      changesCount: int
+      fds: ptr SharedArray[SelectorKey[T]]
+      count: int
+      changesLock: Lock
+    Selector*[T] = ptr SelectorImpl[T]
+else:
+  type
+    SelectorImpl[T] = object
+      kqFD : cint
+      maxFD : int
+      changesTable: array[MAX_KQUEUE_CHANGE_EVENTS, KEvent]
+      changesCount: int
+      fds: seq[SelectorKey[T]]
+      count: int
+    Selector*[T] = ref SelectorImpl[T]
+
+type
+  SelectEventImpl = object
+    rfd: cint
+    wfd: cint
+# SelectEvent is declared as `ptr` to be placed in `shared memory`,
+# so you can share one SelectEvent handle between threads.
+type SelectEvent* = ptr SelectEventImpl
+
+proc newSelector*[T](): Selector[T] =
+  var maxFD = 0.cint
+  var size = sizeof(cint)
+  var namearr = [1.cint, MAX_DESCRIPTORS_ID.cint]
+  # Obtain maximum number of file descriptors for process
+  if sysctl(addr(namearr[0]), 2, cast[pointer](addr maxFD), addr size,
+            nil, 0) != 0:
+    raiseOsError(osLastError())
+
+  var kqFD = kqueue()
+  if kqFD < 0:
+    raiseOsError(osLastError())
+
+  when hasThreadSupport:
+    result = cast[Selector[T]](allocShared0(sizeof(SelectorImpl[T])))
+    result.kqFD = kqFD
+    result.maxFD = maxFD.int
+    result.fds = allocSharedArray[SelectorKey[T]](maxFD)
+    initLock(result.changesLock)
+  else:
+    result = Selector[T]()
+    result.kqFD = kqFD
+    result.maxFD = maxFD.int
+    result.fds = newSeq[SelectorKey[T]](maxFD)
+
+proc close*[T](s: Selector[T]) =
+  if posix.close(s.kqFD) != 0:
+    raiseOSError(osLastError())
+  when hasThreadSupport:
+    deinitLock(s.changesLock)
+    deallocSharedArray(s.fds)
+    deallocShared(cast[pointer](s))
+
+proc newSelectEvent*(): SelectEvent =
+  var fds: array[2, cint]
+  if posix.pipe(fds) == -1:
+    raiseOSError(osLastError())
+  setNonBlocking(fds[0])
+  setNonBlocking(fds[1])
+  result = cast[SelectEvent](allocShared0(sizeof(SelectEventImpl)))
+  result.rfd = fds[0]
+  result.wfd = fds[1]
+
+proc setEvent*(ev: SelectEvent) =
+  var data: uint64 = 1
+  if posix.write(ev.wfd, addr data, sizeof(uint64)) != sizeof(uint64):
+    raiseOSError(osLastError())
+
+proc close*(ev: SelectEvent) =
+  discard posix.close(cint(ev.rfd))
+  discard posix.close(cint(ev.wfd))
+  deallocShared(cast[pointer](ev))
+
+template checkFd(s, f) =
+  if f >= s.maxFD:
+    raise newException(ValueError, "Maximum file descriptors exceeded")
+
+when hasThreadSupport:
+  template withChangeLock[T](s: Selector[T], body: untyped) =
+    acquire(s.changesLock)
+    {.locks: [s.changesLock].}:
+      try:
+        body
+      finally:
+        release(s.changesLock)
+else:
+  template withChangeLock(s, body: untyped) =
+    body
+
+template modifyKQueue[T](s: Selector[T], nident: uint, nfilter: cshort,
+                         nflags: cushort, nfflags: cuint, ndata: int,
+                         nudata: pointer) =
+  mixin withChangeLock
+  s.withChangeLock():
+    s.changesTable[s.changesCount] = KEvent(ident: nident,
+                                            filter: nfilter, flags: nflags,
+                                            fflags: nfflags, data: ndata,
+                                            udata: nudata)
+    inc(s.changesCount)
+    if s.changesCount == MAX_KQUEUE_CHANGE_EVENTS:
+      if kevent(s.kqFD, addr(s.changesTable[0]), cint(s.changesCount),
+                nil, 0, nil) == -1:
+        raiseOSError(osLastError())
+      s.changesCount = 0
+
+proc registerHandle*[T](s: Selector[T], fd: SocketHandle,
+                        events: set[Event], data: T) =
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+  s.setKey(fdi, fdi, events, 0, data)
+  if events != {}:
+    if Event.Read in events:
+      modifyKQueue(s, fdi.uint, EVFILT_READ, EV_ADD, 0, 0, nil)
+      inc(s.count)
+    if Event.Write in events:
+      modifyKQueue(s, fdi.uint, EVFILT_WRITE, EV_ADD, 0, 0, nil)
+      inc(s.count)
+
+proc updateHandle*[T](s: Selector[T], fd: SocketHandle,
+                      events: set[Event]) =
+  let maskEvents = {Event.Timer, Event.Signal, Event.Process, Event.Vnode,
+                    Event.User, Event.Oneshot, Event.Error}
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+  doAssert(pkey.events * maskEvents == {})
+
+  if pkey.events != events:
+    if (Event.Read in pkey.events) and (Event.Read notin events):
+      modifyKQueue(s, fdi.uint, EVFILT_READ, EV_DELETE, 0, 0, nil)
+      dec(s.count)
+    if (Event.Write in pkey.events) and (Event.Write notin events):
+      modifyKQueue(s, fdi.uint, EVFILT_WRITE, EV_DELETE, 0, 0, nil)
+      dec(s.count)
+    if (Event.Read notin pkey.events) and (Event.Read in events):
+      modifyKQueue(s, fdi.uint, EVFILT_READ, EV_ADD, 0, 0, nil)
+      inc(s.count)
+    if (Event.Write notin pkey.events) and (Event.Write in events):
+      modifyKQueue(s, fdi.uint, EVFILT_WRITE, EV_ADD, 0, 0, nil)
+      inc(s.count)
+    pkey.events = events
+
+proc registerTimer*[T](s: Selector[T], timeout: int, oneshot: bool,
+                       data: T): int {.discardable.} =
+  var fdi = posix.socket(posix.AF_INET, posix.SOCK_STREAM,
+                         posix.IPPROTO_TCP).int
+  if fdi == -1:
+    raiseOsError(osLastError())
+
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+
+  let events = if oneshot: {Event.Timer, Event.Oneshot} else: {Event.Timer}
+  let flags: cushort = if oneshot: EV_ONESHOT or EV_ADD else: EV_ADD
+
+  s.setKey(fdi, fdi, events, 0, data)
+  # EVFILT_TIMER on Open/Net(BSD) has granularity of only milliseconds,
+  # but MacOS and FreeBSD allow use `0` as `fflags` to use milliseconds
+  # too
+  modifyKQueue(s, fdi.uint, EVFILT_TIMER, flags, 0, cint(timeout), nil)
+  inc(s.count)
+  result = fdi
+
+proc registerSignal*[T](s: Selector[T], signal: int,
+                        data: T): int {.discardable.} =
+  var fdi = posix.socket(posix.AF_INET, posix.SOCK_STREAM,
+                         posix.IPPROTO_TCP).int
+  if fdi == -1:
+    raiseOsError(osLastError())
+
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+
+  s.setKey(fdi, signal, {Event.Signal}, signal, data)
+  var nmask, omask: Sigset
+  discard sigemptyset(nmask)
+  discard sigemptyset(omask)
+  discard sigaddset(nmask, cint(signal))
+  blockSignals(nmask, omask)
+  # to be compatible with linux semantic we need to "eat" signals
+  posix.signal(cint(signal), SIG_IGN)
+  modifyKQueue(s, signal.uint, EVFILT_SIGNAL, EV_ADD, 0, 0,
+               cast[pointer](fdi))
+  inc(s.count)
+  result = fdi
+
+proc registerProcess*[T](s: Selector[T], pid: int,
+                             data: T): int {.discardable.} =
+  var fdi = posix.socket(posix.AF_INET, posix.SOCK_STREAM,
+                         posix.IPPROTO_TCP).int
+  if fdi == -1:
+    raiseOsError(osLastError())
+
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+
+  var kflags: cushort = EV_ONESHOT or EV_ADD
+  setKey(s, fdi, pid, {Event.Process, Event.Oneshot}, pid, data)
+  modifyKQueue(s, pid.uint, EVFILT_PROC, kflags, NOTE_EXIT, 0,
+               cast[pointer](fdi))
+  inc(s.count)
+  result = fdi
+
+proc registerEvent*[T](s: Selector[T], ev: SelectEvent, data: T) =
+  let fdi = ev.rfd.int
+  doAssert(s.fds[fdi].ident == 0)
+  setKey(s, fdi, fdi, {Event.User}, 0, data)
+  modifyKQueue(s, fdi.uint, EVFILT_READ, EV_ADD, 0, 0, nil)
+  inc(s.count)
+
+proc unregister*[T](s: Selector[T], fd: int|SocketHandle) =
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+
+  if pkey.events != {}:
+    if pkey.events * {Event.Read, Event.Write} != {}:
+      if Event.Read in pkey.events:
+        modifyKQueue(s, fdi.uint, EVFILT_READ, EV_DELETE, 0, 0, nil)
+        dec(s.count)
+      if Event.Write in pkey.events:
+        modifyKQueue(s, fdi.uint, EVFILT_WRITE, EV_DELETE, 0, 0, nil)
+        dec(s.count)
+    elif Event.Timer in pkey.events:
+      discard posix.close(cint(pkey.key.fd))
+      modifyKQueue(s, fdi.uint, EVFILT_TIMER, EV_DELETE, 0, 0, nil)
+      dec(s.count)
+    elif Event.Signal in pkey.events:
+      var nmask, omask: Sigset
+      var signal = cint(pkey.param)
+      discard sigemptyset(nmask)
+      discard sigemptyset(omask)
+      discard sigaddset(nmask, signal)
+      unblockSignals(nmask, omask)
+      posix.signal(signal, SIG_DFL)
+      discard posix.close(cint(pkey.key.fd))
+      modifyKQueue(s, fdi.uint, EVFILT_SIGNAL, EV_DELETE, 0, 0, nil)
+      dec(s.count)
+    elif Event.Process in pkey.events:
+      discard posix.close(cint(pkey.key.fd))
+      modifyKQueue(s, fdi.uint, EVFILT_PROC, EV_DELETE, 0, 0, nil)
+      dec(s.count)
+    elif Event.User in pkey.events:
+      modifyKQueue(s, fdi.uint, EVFILT_READ, EV_DELETE, 0, 0, nil)
+      dec(s.count)
+  pkey.ident = 0
+  pkey.events = {}
+
+proc unregister*[T](s: Selector[T], ev: SelectEvent) =
+  let fdi = int(ev.rfd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+  doAssert(Event.User in pkey.events)
+  pkey.ident = 0
+  pkey.events = {}
+  modifyKQueue(s, fdi.uint, EVFILT_READ, EV_DELETE, 0, 0, nil)
+  dec(s.count)
+
+proc flush*[T](s: Selector[T]) =
+  s.withChangeLock():
+    var tv = Timespec()
+    if kevent(s.kqFD, addr(s.changesTable[0]), cint(s.changesCount),
+              nil, 0, addr tv) == -1:
+      raiseOSError(osLastError())
+    s.changesCount = 0
+
+proc selectInto*[T](s: Selector[T], timeout: int,
+                    results: var openarray[ReadyKey[T]]): int =
+  var
+    tv: Timespec
+    resTable: array[MAX_KQUEUE_RESULT_EVENTS, KEvent]
+    ptv = addr tv
+    maxres = MAX_KQUEUE_RESULT_EVENTS
+
+  if timeout != -1:
+    if timeout >= 1000:
+      tv.tv_sec = (timeout div 1_000).Time
+      tv.tv_nsec = (timeout %% 1_000) * 1_000_000
+    else:
+      tv.tv_sec = 0.Time
+      tv.tv_nsec = timeout * 1_000_000
+  else:
+    ptv = nil
+
+  if maxres > len(results):
+    maxres = len(results)
+
+  var count = 0
+  s.withChangeLock():
+    count = kevent(s.kqFD, addr(s.changesTable[0]), cint(s.changesCount),
+                   addr(resTable[0]), cint(maxres), ptv)
+    s.changesCount = 0
+
+  if count < 0:
+    result = 0
+    let err = osLastError()
+    if cint(err) != EINTR:
+      raiseOSError(err)
+  elif count == 0:
+    result = 0
+  else:
+    var i = 0
+    var k = 0
+    var pkey: ptr SelectorKey[T]
+    while i < count:
+      let kevent = addr(resTable[i])
+      if (kevent.flags and EV_ERROR) == 0:
+        case kevent.filter:
+        of EVFILT_READ:
+          pkey = addr(s.fds[kevent.ident.int])
+          pkey.key.events = {Event.Read}
+          if Event.User in pkey.events:
+            var data: uint64 = 0
+            if posix.read(kevent.ident.cint, addr data,
+                          sizeof(uint64)) != sizeof(uint64):
+              let err = osLastError()
+              if err == OSErrorCode(EAGAIN):
+                # someone already consumed event data
+                inc(i)
+                continue
+              else:
+                raiseOSError(osLastError())
+            pkey.key.events = {Event.User}
+        of EVFILT_WRITE:
+          pkey = addr(s.fds[kevent.ident.int])
+          pkey.key.events = {Event.Write}
+        of EVFILT_TIMER:
+          pkey = addr(s.fds[kevent.ident.int])
+          if Event.Oneshot in pkey.events:
+            if posix.close(cint(pkey.ident)) == -1:
+              raiseOSError(osLastError())
+            pkey.ident = 0
+            pkey.events = {}
+            dec(s.count)
+          pkey.key.events = {Event.Timer}
+        of EVFILT_VNODE:
+          pkey = addr(s.fds[kevent.ident.int])
+          pkey.key.events = {Event.Vnode}
+        of EVFILT_SIGNAL:
+          pkey = addr(s.fds[cast[int](kevent.udata)])
+          pkey.key.events = {Event.Signal}
+        of EVFILT_PROC:
+          pkey = addr(s.fds[cast[int](kevent.udata)])
+          if posix.close(cint(pkey.ident)) == -1:
+            raiseOSError(osLastError())
+          pkey.ident = 0
+          pkey.events = {}
+          dec(s.count)
+          pkey.key.events = {Event.Process}
+        else:
+          raise newException(ValueError, "Unsupported kqueue filter in queue")
+
+        if (kevent.flags and EV_EOF) != 0:
+          pkey.key.events.incl(Event.Error)
+
+        results[k] = pkey.key
+        inc(k)
+      inc(i)
+    result = k
+
+proc select*[T](s: Selector[T], timeout: int): seq[ReadyKey[T]] =
+  result = newSeq[ReadyKey[T]](MAX_KQUEUE_RESULT_EVENTS)
+  let count = selectInto(s, timeout, result)
+  result.setLen(count)
+
+template isEmpty*[T](s: Selector[T]): bool =
+  (s.count == 0)
+
+template withData*[T](s: Selector[T], fd: SocketHandle, value,
+                        body: untyped) =
+  mixin checkFd
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  if s.fds[fdi].ident != 0:
+    var value = addr(s.fds[fdi].key.data)
+    body
+
+template withData*[T](s: Selector[T], fd: SocketHandle, value, body1,
+                        body2: untyped) =
+  mixin checkFd
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  if s.fds[fdi].ident != 0:
+    var value = addr(s.fds[fdi].key.data)
+    body1
+  else:
+    body2
--- a/lib/pure/ioselects/ioselectors_poll.nim
+++ b/lib/pure/ioselects/ioselectors_poll.nim
@@ -0,0 +1,295 @@
+#
+#
+#            Nim's Runtime Library
+#        (c) Copyright 2016 Eugene Kabanov
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+# This module implements Posix poll().
+
+import posix, times
+
+# Maximum number of events that can be returned
+const MAX_POLL_RESULT_EVENTS = 64
+
+when hasThreadSupport:
+  type
+    SelectorImpl[T] = object
+      maxFD : int
+      pollcnt: int
+      fds: ptr SharedArray[SelectorKey[T]]
+      pollfds: ptr SharedArray[TPollFd]
+      count: int
+      lock: Lock
+    Selector*[T] = ptr SelectorImpl[T]
+else:
+  type
+    SelectorImpl[T] = object
+      maxFD : int
+      pollcnt: int
+      fds: seq[SelectorKey[T]]
+      pollfds: seq[TPollFd]
+      count: int
+    Selector*[T] = ref SelectorImpl[T]
+
+type
+  SelectEventImpl = object
+    rfd: cint
+    wfd: cint
+  SelectEvent* = ptr SelectEventImpl
+
+var RLIMIT_NOFILE {.importc: "RLIMIT_NOFILE",
+                    header: "<sys/resource.h>".}: cint
+type
+  rlimit {.importc: "struct rlimit",
+           header: "<sys/resource.h>", pure, final.} = object
+    rlim_cur: int
+    rlim_max: int
+proc getrlimit(resource: cint, rlp: var rlimit): cint
+     {.importc: "getrlimit",header: "<sys/resource.h>".}
+
+when hasThreadSupport:
+  template withPollLock[T](s: Selector[T], body: untyped) =
+    acquire(s.lock)
+    {.locks: [s.lock].}:
+      try:
+        body
+      finally:
+        release(s.lock)
+else:
+  template withPollLock(s, body: untyped) =
+    body
+
+proc newSelector*[T](): Selector[T] =
+  var a = rlimit()
+  if getrlimit(RLIMIT_NOFILE, a) != 0:
+    raiseOsError(osLastError())
+  var maxFD = int(a.rlim_max)
+
+  when hasThreadSupport:
+    result = cast[Selector[T]](allocShared0(sizeof(SelectorImpl[T])))
+    result.maxFD = maxFD
+    result.fds = allocSharedArray[SelectorKey[T]](maxFD)
+    result.pollfds = allocSharedArray[TPollFd](maxFD)
+    initLock(result.lock)
+  else:
+    result = Selector[T]()
+    result.maxFD = maxFD
+    result.fds = newSeq[SelectorKey[T]](maxFD)
+    result.pollfds = newSeq[TPollFd](maxFD)
+
+proc close*[T](s: Selector[T]) =
+  when hasThreadSupport:
+    deinitLock(s.lock)
+    deallocSharedArray(s.fds)
+    deallocSharedArray(s.pollfds)
+    deallocShared(cast[pointer](s))
+
+template pollAdd[T](s: Selector[T], sock: cint, events: set[Event]) =
+  withPollLock(s):
+    var pollev: cshort = 0
+    if Event.Read in events: pollev = pollev or POLLIN
+    if Event.Write in events: pollev = pollev or POLLOUT
+    s.pollfds[s.pollcnt].fd = cint(sock)
+    s.pollfds[s.pollcnt].events = pollev
+    inc(s.count)
+    inc(s.pollcnt)
+
+template pollUpdate[T](s: Selector[T], sock: cint, events: set[Event]) =
+  withPollLock(s):
+    var i = 0
+    var pollev: cshort = 0
+    if Event.Read in events: pollev = pollev or POLLIN
+    if Event.Write in events: pollev = pollev or POLLOUT
+
+    while i < s.pollcnt:
+      if s.pollfds[i].fd == sock:
+        s.pollfds[i].events = pollev
+        break
+      inc(i)
+
+    if i == s.pollcnt:
+      raise newException(ValueError, "Descriptor is not registered in queue")
+
+template pollRemove[T](s: Selector[T], sock: cint) =
+  withPollLock(s):
+    var i = 0
+    while i < s.pollcnt:
+      if s.pollfds[i].fd == sock:
+        if i == s.pollcnt - 1:
+          s.pollfds[i].fd = 0
+          s.pollfds[i].events = 0
+          s.pollfds[i].revents = 0
+        else:
+          while i < (s.pollcnt - 1):
+            s.pollfds[i].fd = s.pollfds[i + 1].fd
+            s.pollfds[i].events = s.pollfds[i + 1].events
+            inc(i)
+        break
+      inc(i)
+    dec(s.pollcnt)
+    dec(s.count)
+
+template checkFd(s, f) =
+  if f >= s.maxFD:
+    raise newException(ValueError, "Maximum file descriptors exceeded")
+
+proc registerHandle*[T](s: Selector[T], fd: SocketHandle,
+                        events: set[Event], data: T) =
+  var fdi = int(fd)
+  s.checkFd(fdi)
+  doAssert(s.fds[fdi].ident == 0)
+  s.setKey(fdi, fdi, events, 0, data)
+  if events != {}: s.pollAdd(fdi.cint, events)
+
+proc updateHandle*[T](s: Selector[T], fd: SocketHandle,
+                      events: set[Event]) =
+  let maskEvents = {Event.Timer, Event.Signal, Event.Process, Event.Vnode,
+                    Event.User, Event.Oneshot, Event.Error}
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+  doAssert(pkey.events * maskEvents == {})
+
+  if pkey.events != events:
+    if pkey.events == {}:
+      s.pollAdd(fd.cint, events)
+    else:
+      if events != {}:
+        s.pollUpdate(fd.cint, events)
+      else:
+        s.pollRemove(fd.cint)
+    pkey.events = events
+
+proc registerEvent*[T](s: Selector[T], ev: SelectEvent, data: T) =
+  var fdi = int(ev.rfd)
+  doAssert(s.fds[fdi].ident == 0)
+  var events = {Event.User}
+  setKey(s, fdi, fdi, events, 0, data)
+  events.incl(Event.Read)
+  s.pollAdd(fdi.cint, events)
+
+proc flush*[T](s: Selector[T]) = discard
+
+proc unregister*[T](s: Selector[T], fd: int|SocketHandle) =
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+  pkey.ident = 0
+  pkey.events = {}
+  s.pollRemove(fdi.cint)
+
+proc unregister*[T](s: Selector[T], ev: SelectEvent) =
+  let fdi = int(ev.rfd)
+  s.checkFd(fdi)
+  var pkey = addr(s.fds[fdi])
+  doAssert(pkey.ident != 0)
+  doAssert(Event.User in pkey.events)
+  pkey.ident = 0
+  pkey.events = {}
+  s.pollRemove(fdi.cint)
+
+proc newSelectEvent*(): SelectEvent =
+  var fds: array[2, cint]
+  if posix.pipe(fds) == -1:
+    raiseOSError(osLastError())
+  setNonBlocking(fds[0])
+  setNonBlocking(fds[1])
+  result = cast[SelectEvent](allocShared0(sizeof(SelectEventImpl)))
+  result.rfd = fds[0]
+  result.wfd = fds[1]
+
+proc setEvent*(ev: SelectEvent) =
+  var data: uint64 = 1
+  if posix.write(ev.wfd, addr data, sizeof(uint64)) != sizeof(uint64):
+    raiseOSError(osLastError())
+
+proc close*(ev: SelectEvent) =
+  discard posix.close(cint(ev.rfd))
+  discard posix.close(cint(ev.wfd))
+  deallocShared(cast[pointer](ev))
+
+proc selectInto*[T](s: Selector[T], timeout: int,
+                    results: var openarray[ReadyKey[T]]): int =
+  var maxres = MAX_POLL_RESULT_EVENTS
+  if maxres > len(results):
+    maxres = len(results)
+
+  s.withPollLock():
+    let count = posix.poll(addr(s.pollfds[0]), Tnfds(s.pollcnt), timeout)
+    if count < 0:
+      result = 0
+      let err = osLastError()
+      if err.cint == EINTR:
+        discard
+      else:
+        raiseOSError(osLastError())
+    elif count == 0:
+      result = 0
+    else:
+      var i = 0
+      var k = 0
+      var rindex = 0
+      while (i < s.pollcnt) and (k < count) and (rindex < maxres):
+        let revents = s.pollfds[i].revents
+        if revents != 0:
+          let fd = s.pollfds[i].fd
+          var skey = addr(s.fds[fd])
+          skey.key.events = {}
+
+          if (revents and POLLIN) != 0:
+            skey.key.events.incl(Event.Read)
+            if Event.User in skey.events:
+              var data: uint64 = 0
+              if posix.read(fd, addr data, sizeof(int)) != sizeof(int):
+                let err = osLastError()
+                if err != OSErrorCode(EAGAIN):
+                  raiseOSError(osLastError())
+                else:
+                  # someone already consumed event data
+                  inc(i)
+                  continue
+              skey.key.events = {Event.User}
+          if (revents and POLLOUT) != 0:
+            skey.key.events.incl(Event.Write)
+          if (revents and POLLERR) != 0 or (revents and POLLHUP) != 0 or
+             (revents and POLLNVAL) != 0:
+            skey.key.events.incl(Event.Error)
+          results[rindex] = skey.key
+          s.pollfds[i].revents = 0
+          inc(rindex)
+          inc(k)
+        inc(i)
+      result = k
+
+proc select*[T](s: Selector[T], timeout: int): seq[ReadyKey[T]] =
+  result = newSeq[ReadyKey[T]](MAX_POLL_RESULT_EVENTS)
+  let count = selectInto(s, timeout, result)
+  result.setLen(count)
+
+template isEmpty*[T](s: Selector[T]): bool =
+  (s.count == 0)
+
+template withData*[T](s: Selector[T], fd: SocketHandle, value,
+                        body: untyped) =
+  mixin checkFd
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  if s.fds[fdi].ident != 0:
+    var value = addr(s.fds[fdi].key.data)
+    body
+
+template withData*[T](s: Selector[T], fd: SocketHandle, value, body1,
+                        body2: untyped) =
+  mixin checkFd
+  let fdi = int(fd)
+  s.checkFd(fdi)
+  if s.fds[fdi].ident != 0:
+    var value = addr(s.fds[fdi].key.data)
+    body1
+  else:
+    body2
--- a/lib/pure/ioselects/ioselectors_select.nim
+++ b/lib/pure/ioselects/ioselectors_select.nim
@@ -0,0 +1,416 @@
+#
+#
+#            Nim's Runtime Library
+#        (c) Copyright 2016 Eugene Kabanov
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+# This module implements Posix and Windows select().
+
+import times, nativesockets
+
+when defined(windows):
+  import winlean
+  when defined(gcc):
+    {.passL: "-lws2_32".}
+  elif defined(vcc):
+    {.passL: "ws2_32.lib".}
+  const platformHeaders = """#include <winsock2.h>
+                             #include <windows.h>"""
+  const EAGAIN = WSAEWOULDBLOCK
+else:
+  const platformHeaders = """#include <sys/select.h>
+                             #include <sys/time.h>
+                             #include <sys/types.h>
+                             #include <unistd.h>"""
+type
+  Fdset {.importc: "fd_set", header: platformHeaders, pure, final.} = object
+var
+  FD_SETSIZE {.importc: "FD_SETSIZE", header: platformHeaders.}: cint
+
+proc IOFD_SET(fd: SocketHandle, fdset: ptr Fdset)
+     {.cdecl, importc: "FD_SET", header: platformHeaders, inline.}
+proc IOFD_CLR(fd: SocketHandle, fdset: ptr Fdset)
+     {.cdecl, importc: "FD_CLR", header: platformHeaders, inline.}
+proc IOFD_ZERO(fdset: ptr Fdset)
+     {.cdecl, importc: "FD_ZERO", header: platformHeaders, inline.}
+
+when defined(windows):
+  proc IOFD_ISSET(fd: SocketHandle, fdset: ptr Fdset): cint
+       {.stdcall, importc: "FD_ISSET", header: platformHeaders, inline.}
+  proc ioselect(nfds: cint, readFds, writeFds, exceptFds: ptr Fdset,
+                timeout: ptr Timeval): cint
+       {.stdcall, importc: "select", header: platformHeaders.}
+else:
+  proc IOFD_ISSET(fd: SocketHandle, fdset: ptr Fdset): cint
+       {.cdecl, importc: "FD_ISSET", header: platformHeaders, inline.}
+  proc ioselect(nfds: cint, readFds, writeFds, exceptFds: ptr Fdset,
+                timeout: ptr Timeval): cint
+       {.cdecl, importc: "select", header: platformHeaders.}
+
+when hasThreadSupport:
+  type
+    SelectorImpl[T] = object
+      rSet: FdSet
+      wSet: FdSet
+      eSet: FdSet
+      maxFD: int
+      fds: ptr SharedArray[SelectorKey[T]]
+      count: int
+      lock: Lock
+    Selector*[T] = ptr SelectorImpl[T]
+else:
+  type
+    SelectorImpl[T] = object
+      rSet: FdSet
+      wSet: FdSet
+      eSet: FdSet
+      maxFD: int
+      fds: seq[SelectorKey[T]]
+      count: int
+    Selector*[T] = ref SelectorImpl[T]
+
+type
+  SelectEventImpl = object
+    rsock: SocketHandle
+    wsock: SocketHandle
+  SelectEvent* = ptr SelectEventImpl
+
+when hasThreadSupport:
+  template withSelectLock[T](s: Selector[T], body: untyped) =
+    acquire(s.lock)
+    {.locks: [s.lock].}:
+      try:
+        body
+      finally:
+        release(s.lock)
+else:
+  template withSelectLock[T](s: Selector[T], body: untyped) =
+    body
+
+proc newSelector*[T](): Selector[T] =
+  when hasThreadSupport:
+    result = cast[Selector[T]](allocShared0(sizeof(SelectorImpl[T])))
+    result.fds = allocSharedArray[SelectorKey[T]](FD_SETSIZE)
+    initLock result.lock
+  else:
+    result = Selector[T]()
+    result.fds = newSeq[SelectorKey[T]](FD_SETSIZE)
+
+  IOFD_ZERO(addr result.rSet)
+  IOFD_ZERO(addr result.wSet)
+  IOFD_ZERO(addr result.eSet)
+
+proc close*[T](s: Selector[T]) =
+  when hasThreadSupport:
+    deallocSharedArray(s.fds)
+    deallocShared(cast[pointer](s))
+
+when defined(windows):
+  proc newSelectEvent*(): SelectEvent =
+    var ssock = newNativeSocket()
+    var wsock = newNativeSocket()
+    var rsock: SocketHandle = INVALID_SOCKET
+    var saddr = Sockaddr_in()
+
+    saddr.sin_family = winlean.AF_INET
+    saddr.sin_port = 0
+    saddr.sin_addr.s_addr = INADDR_ANY
+    if bindAddr(ssock, cast[ptr SockAddr](addr(saddr)),
+                sizeof(saddr).SockLen) < 0'i32:
+      raiseOSError(osLastError())
+
+    if winlean.listen(ssock, 1) == -1:
+      raiseOSError(osLastError())
+
+    var namelen = sizeof(saddr).SockLen
+    if getsockname(ssock, cast[ptr SockAddr](addr(saddr)),
+                   addr(namelen)) == -1'i32:
+      raiseOSError(osLastError())
+
+    saddr.sin_addr.s_addr = 0x0100007F
+    if winlean.connect(wsock, cast[ptr SockAddr](addr(saddr)),
+                       sizeof(saddr).SockLen) == -1:
+      raiseOSError(osLastError())
+    namelen = sizeof(saddr).SockLen
+    rsock = winlean.accept(ssock, cast[ptr SockAddr](addr(saddr)),
+                           cast[ptr SockLen](addr(namelen)))
+    if rsock == SocketHandle(-1):
+      raiseOSError(osLastError())
+
+    if winlean.closesocket(ssock) == -1:
+      raiseOSError(osLastError())
+
+    var mode = clong(1)
+    if ioctlsocket(rsock, FIONBIO, addr(mode)) == -1:
+      raiseOSError(osLastError())
+    mode = clong(1)
+    if ioctlsocket(wsock, FIONBIO, addr(mode)) == -1:
+      raiseOSError(osLastError())
+
+    result = cast[SelectEvent](allocShared0(sizeof(SelectEventImpl)))
+    result.rsock = rsock
+    result.wsock = wsock
+
+  proc setEvent*(ev: SelectEvent) =
+    var data: int = 1
+    if winlean.send(ev.wsock, cast[pointer](addr data),
+                    cint(sizeof(int)), 0) != sizeof(int):
+      raiseOSError(osLastError())
+
+  proc close*(ev: SelectEvent) =
+    discard winlean.closesocket(ev.rsock)
+    discard winlean.closesocket(ev.wsock)
+    deallocShared(cast[pointer](ev))
+
+else:
+  proc newSelectEvent*(): SelectEvent =
+    var fds: array[2, cint]
+    if posix.pipe(fds) == -1:
+      raiseOSError(osLastError())
+    setNonBlocking(fds[0])
+    setNonBlocking(fds[1])
+    result = cast[SelectEvent](allocShared0(sizeof(SelectEventImpl)))
+    result.rsock = SocketHandle(fds[0])
+    result.wsock = SocketHandle(fds[1])
+
+  proc setEvent*(ev: SelectEvent) =
+    var data: uint64 = 1
+    if posix.write(cint(ev.wsock), addr data, sizeof(uint64)) != sizeof(uint64):
+      raiseOSError(osLastError())
+
+  proc close*(ev: SelectEvent) =
+    discard posix.close(cint(ev.rsock))
+    discard posix.close(cint(ev.wsock))
+    deallocShared(cast[pointer](ev))
+
+proc setKey[T](s: Selector[T], fd: SocketHandle, events: set[Event], data: T) =
+  var i = 0
+  let fdi = int(fd)
+  while i < FD_SETSIZE:
+    if s.fds[i].ident == 0:
+      var pkey = addr(s.fds[i])
+      pkey.ident = fdi
+      pkey.events = events
+      pkey.key.fd = fd.int
+      pkey.key.events = {}
+      pkey.key.data = data
+      break
+    inc(i)
+  if i == FD_SETSIZE:
+    raise newException(ValueError, "Maximum numbers of fds exceeded")
+
+proc getKey[T](s: Selector[T], fd: SocketHandle): ptr SelectorKey[T] =
+  var i = 0
+  let fdi = int(fd)
+  while i < FD_SETSIZE:
+    if s.fds[i].ident == fdi:
+      result = addr(s.fds[i])
+      break
+    inc(i)
+  doAssert(i < FD_SETSIZE, "Descriptor not registered in queue")
+
+proc delKey[T](s: Selector[T], fd: SocketHandle) =
+  var i = 0
+  while i < FD_SETSIZE:
+    if s.fds[i].ident == fd.int:
+      s.fds[i].ident = 0
+      s.fds[i].events = {}
+      break
+    inc(i)
+  doAssert(i < FD_SETSIZE, "Descriptor not registered in queue")
+
+proc registerHandle*[T](s: Selector[T], fd: SocketHandle,
+                        events: set[Event], data: T) =
+  when not defined(windows):
+    let fdi = int(fd)
+  s.withSelectLock():
+    s.setKey(fd, events, data)
+    when not defined(windows):
+      if fdi > s.maxFD: s.maxFD = fdi
+    if Event.Read in events:
+      IOFD_SET(fd, addr s.rSet)
+      inc(s.count)
+    if Event.Write in events:
+      IOFD_SET(fd, addr s.wSet)
+      IOFD_SET(fd, addr s.eSet)
+      inc(s.count)
+
+proc registerEvent*[T](s: Selector[T], ev: SelectEvent, data: T) =
+  when not defined(windows):
+    let fdi = int(ev.rsock)
+  s.withSelectLock():
+    s.setKey(ev.rsock, {Event.User}, data)
+    when not defined(windows):
+      if fdi > s.maxFD: s.maxFD = fdi
+    IOFD_SET(ev.rsock, addr s.rSet)
+    inc(s.count)
+
+proc updateHandle*[T](s: Selector[T], fd: SocketHandle,
+                      events: set[Event]) =
+  let maskEvents = {Event.Timer, Event.Signal, Event.Process, Event.Vnode,
+                    Event.User, Event.Oneshot, Event.Error}
+  s.withSelectLock():
+    var pkey = s.getKey(fd)
+    doAssert(pkey.events * maskEvents == {})
+    if pkey.events != events:
+      if (Event.Read in pkey.events) and (Event.Read notin events):
+        IOFD_CLR(fd, addr s.rSet)
+        dec(s.count)
+      if (Event.Write in pkey.events) and (Event.Write notin events):
+        IOFD_CLR(fd, addr s.wSet)
+        IOFD_CLR(fd, addr s.eSet)
+        dec(s.count)
+      if (Event.Read notin pkey.events) and (Event.Read in events):
+        IOFD_SET(fd, addr s.rSet)
+        inc(s.count)
+      if (Event.Write notin pkey.events) and (Event.Write in events):
+        IOFD_SET(fd, addr s.wSet)
+        IOFD_SET(fd, addr s.eSet)
+        inc(s.count)
+      pkey.events = events
+
+proc unregister*[T](s: Selector[T], fd: SocketHandle) =
+  s.withSelectLock():
+    var pkey = s.getKey(fd)
+    if Event.Read in pkey.events:
+      IOFD_CLR(fd, addr s.rSet)
+      dec(s.count)
+    if Event.Write in pkey.events:
+      IOFD_CLR(fd, addr s.wSet)
+      IOFD_CLR(fd, addr s.eSet)
+      dec(s.count)
+    s.delKey(fd)
+
+proc unregister*[T](s: Selector[T], ev: SelectEvent) =
+  let fd = ev.rsock
+  s.withSelectLock():
+    IOFD_CLR(fd, addr s.rSet)
+    dec(s.count)
+    s.delKey(fd)
+
+proc selectInto*[T](s: Selector[T], timeout: int,
+                    results: var openarray[ReadyKey[T]]): int =
+  var tv = Timeval()
+  var ptv = addr tv
+  var rset, wset, eset: FdSet
+
+  if timeout != -1:
+    tv.tv_sec = timeout.int32 div 1_000
+    tv.tv_usec = (timeout.int32 %% 1_000) * 1_000
+  else:
+    ptv = nil
+
+  s.withSelectLock():
+    rset = s.rSet
+    wset = s.wSet
+    eset = s.eSet
+
+  var count = ioselect(cint(s.maxFD) + 1, addr(rset), addr(wset),
+                       addr(eset), ptv)
+  if count < 0:
+    result = 0
+    when defined(windows):
+      raiseOSError(osLastError())
+    else:
+      let err = osLastError()
+      if cint(err) != EINTR:
+        raiseOSError(err)
+  elif count == 0:
+    result = 0
+  else:
+    var rindex = 0
+    var i = 0
+    var k = 0
+
+    while (i < FD_SETSIZE) and (k < count):
+      if s.fds[i].ident != 0:
+        var flag = false
+        var pkey = addr(s.fds[i])
+        pkey.key.events = {}
+        let fd = SocketHandle(pkey.ident)
+        if IOFD_ISSET(fd, addr rset) != 0:
+          if Event.User in pkey.events:
+            var data: uint64 = 0
+            if recv(fd, cast[pointer](addr(data)),
+                    sizeof(uint64).cint, 0) != sizeof(uint64):
+              let err = osLastError()
+              if cint(err) != EAGAIN:
+                raiseOSError(err)
+              else:
+                inc(i)
+                inc(k)
+                continue
+            else:
+              flag = true
+              pkey.key.events = {Event.User}
+          else:
+            flag = true
+            pkey.key.events = {Event.Read}
+        if IOFD_ISSET(fd, addr wset) != 0:
+          pkey.key.events.incl(Event.Write)
+          if IOFD_ISSET(fd, addr eset) != 0:
+            pkey.key.events.incl(Event.Error)
+          flag = true
+        if flag:
+          results[rindex] = pkey.key
+          inc(rindex)
+          inc(k)
+      inc(i)
+    result = rindex
+
+proc select*[T](s: Selector[T], timeout: int): seq[ReadyKey[T]] =
+  result = newSeq[ReadyKey[T]](FD_SETSIZE)
+  var count = selectInto(s, timeout, result)
+  result.setLen(count)
+
+proc flush*[T](s: Selector[T]) = discard
+
+template isEmpty*[T](s: Selector[T]): bool =
+  (s.count == 0)
+
+when hasThreadSupport:
+  template withSelectLock[T](s: Selector[T], body: untyped) =
+    acquire(s.lock)
+    {.locks: [s.lock].}:
+      try:
+        body
+      finally:
+        release(s.lock)
+else:
+  template withSelectLock[T](s: Selector[T], body: untyped) =
+    body
+
+template withData*[T](s: Selector[T], fd: SocketHandle, value,
+                      body: untyped) =
+  mixin withSelectLock
+  s.withSelectLock():
+    var value: ptr T
+    let fdi = int(fd)
+    var i = 0
+    while i < FD_SETSIZE:
+      if s.fds[i].ident == fdi:
+        value = addr(s.fds[i].key.data)
+        break
+      inc(i)
+    if i != FD_SETSIZE:
+      body
+
+template withData*[T](s: Selector[T], fd: SocketHandle, value,
+                      body1, body2: untyped) =
+  mixin withSelectLock
+  s.withSelectLock():
+    var value: ptr T
+    let fdi = int(fd)
+    var i = 0
+    while i < FD_SETSIZE:
+      if s.fds[i].ident == fdi:
+        value = addr(s.fds[i].key.data)
+        break
+      inc(i)
+    if i != FD_SETSIZE:
+      body1
+    else:
+      body2
--- a/lib/system/osalloc.nim
+++ b/lib/system/osalloc.nim
@@ -150,8 +150,9 @@ elif defined(windows):
    #VirtualFree(p, size, MEM_DECOMMIT)

 elif hostOS == "standalone":
+  const StandaloneHeapSize {.intdefine.}: int = 1024 * PageSize
  var
-    theHeap: array[1024*PageSize, float64] # 'float64' for alignment
+    theHeap: array[StandaloneHeapSize, float64] # 'float64' for alignment
    bumpPointer = cast[int](addr theHeap)

  proc osAllocPages(size: int): pointer {.inline.} =
--- a/lib/system/repr.nim
+++ b/lib/system/repr.nim
@@ -73,23 +73,20 @@ proc reprChar(x: char): string {.compilerRtl.} =
  add result, "\'"

 proc reprEnum(e: int, typ: PNimType): string {.compilerRtl.} =
-  # we read an 'int' but this may have been too large, so mask the other bits:
-  let b = (sizeof(int)-typ.size)*8 # bits
-  let m = 1 shl (b-1) # mask
-  var o = e and ((1 shl b)-1) # clear upper bits
-  o = (o xor m) - m # sign extend
-  # XXX we need a proper narrowing based on signedness here
-  #e and ((1 shl (typ.size*8)) - 1)
+  ## Return string representation for enumeration values
+  var n = typ.node
  if ntfEnumHole notin typ.flags:
-    if o <% typ.node.len:
-      return $typ.node.sons[o].name
+    let o = e - n.sons[0].offset
+    if o >= 0 and o <% typ.node.len:
+      return $n.sons[o].name
  else:
    # ugh we need a slow linear search:
-    var n = typ.node
    var s = n.sons
    for i in 0 .. n.len-1:
-      if s[i].offset == o: return $s[i].name
-  result = $o & " (invalid data!)"
+      if s[i].offset == e:
+        return $s[i].name
+
+  result = $e & " (invalid data!)"

 type
  PByteArray = ptr array[0.. 0xffff, int8]
--- a/lib/upcoming/asyncdispatch.nim
+++ b/lib/upcoming/asyncdispatch.nim
--- a/tests/async/tioselectors.nim
+++ b/tests/async/tioselectors.nim
@@ -124,7 +124,7 @@ when not defined(windows):

  proc event_notification_test(): bool =
    var selector = newSelector[int]()
-    var event = newEvent()
+    var event = newSelectEvent()
    selector.registerEvent(event, 1)
    selector.flush()
    event.setEvent()
@@ -235,7 +235,7 @@ when not defined(windows):
        thr: array [0..7, Thread[SelectEvent]]
      var selector = newSelector[int]()
      var sock = newNativeSocket()
-      var event = newEvent()
+      var event = newSelectEvent()
      for i in 0..high(thr):
        createThread(thr[i], event_wait_thread, event)
      selector.registerHandle(sock, {Event.Read}, 1)
@@ -358,7 +358,7 @@ else:

  proc event_notification_test(): bool =
    var selector = newSelector[int]()
-    var event = newEvent()
+    var event = newSelectEvent()
    selector.registerEvent(event, 1)
    selector.flush()
    event.setEvent()
@@ -391,7 +391,7 @@ else:

    proc mt_event_test(): bool =
      var thr: array [0..7, Thread[SelectEvent]]
-      var event = newEvent()
+      var event = newSelectEvent()
      for i in 0..high(thr):
        createThread(thr[i], event_wait_thread, event)
      event.setEvent()
--- a/tests/vm/tvmmisc.nim
+++ b/tests/vm/tvmmisc.nim
@@ -0,0 +1,6 @@
+
+# 4412
+proc default[T](t: typedesc[T]): T {.inline.} = discard
+
+static:
+  var x = default(type(0))
--- a/web/news/version_0_15_released.rst
+++ b/web/news/version_0_15_released.rst
@@ -46,8 +46,14 @@ Library Additions
 Compiler Additions
 ------------------

+- The ``-d/--define`` flag can now optionally take a value to be used
+  by code at compile time.
+
 Language Additions
 ------------------

+- Added ``{.intdefine.}`` and ``{.strdefine.}`` macros to make use of
+  (optional) compile time defines.
+
 Bugfixes
 --------