diff --git a/compiler/ast.nim b/compiler/ast.nim
index 4001e896e3..25958f580b 100644
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@@ -784,6 +784,7 @@ type
       tab*: TStrTable         # interface table for modules
     of skLet, skVar, skField, skForVar:
       guard*: PSym
+      bitsize*: int
     else: nil
     magic*: TMagic
     typ*: PType
diff --git a/compiler/ccgtypes.nim b/compiler/ccgtypes.nim
index 84d02d1da6..1ed9ce1139 100644
--- a/compiler/ccgtypes.nim
+++ b/compiler/ccgtypes.nim
@@ -441,6 +441,8 @@ proc genRecordFieldsAux(m: BModule, n: PNode,
       elif fieldType.kind == tySequence:
         # we need to use a weak dependency here for trecursive_table.
         addf(result, "$1 $2;$n", [getTypeDescWeak(m, field.loc.t, check), sname])
+      elif field.bitsize != 0:
+        addf(result, "$1 $2:$3;$n", [getTypeDescAux(m, field.loc.t, check), sname, rope($field.bitsize)])
       else:
         # don't use fieldType here because we need the
         # tyGenericInst for C++ template support
diff --git a/compiler/extccomp.nim b/compiler/extccomp.nim
index 29aa03c94c..3882bdd036 100644
--- a/compiler/extccomp.nim
+++ b/compiler/extccomp.nim
@@ -14,7 +14,7 @@
 
 import
   lists, ropes, os, strutils, osproc, platform, condsyms, options, msgs,
-  securehash
+  securehash, streams
 
 type
   TSystemCC* = enum
@@ -672,6 +672,12 @@ proc callCCompiler*(projectfile: string) =
   var prettyCmds: TStringSeq = @[]
   let prettyCb = proc (idx: int) =
     echo prettyCmds[idx]
+  let runCb = proc (idx: int, p: Process) =
+    let exitCode = p.peekExitCode
+    if exitCode != 0:
+      rawMessage(errGenerated, "execution of an external compiler program '" &
+        cmds[idx] & "' failed with exit code: " & $exitCode & "\n\n" &
+        p.outputStream.readAll.strip)
   compileCFile(toCompile, script, cmds, prettyCmds, false)
   compileCFile(externalToCompile, script, cmds, prettyCmds, true)
   if optCompileOnly notin gGlobalOptions:
@@ -682,22 +688,17 @@ proc callCCompiler*(projectfile: string) =
         res = execWithEcho(cmds[i])
         if res != 0: rawMessage(errExecutionOfProgramFailed, cmds[i])
     elif optListCmd in gGlobalOptions or gVerbosity > 1:
-      res = execProcesses(cmds, {poEchoCmd, poUsePath, poParentStreams},
-                          gNumberOfProcessors)
+      res = execProcesses(cmds, {poEchoCmd, poStdErrToStdOut, poUsePath, poParentStreams},
+                          gNumberOfProcessors, afterRunEvent=runCb)
     elif gVerbosity == 1:
-      res = execProcesses(cmds, {poUsePath, poParentStreams},
-                          gNumberOfProcessors, prettyCb)
+      res = execProcesses(cmds, {poStdErrToStdOut, poUsePath, poParentStreams},
+                          gNumberOfProcessors, prettyCb, afterRunEvent=runCb)
     else:
-      res = execProcesses(cmds, {poUsePath, poParentStreams},
-                          gNumberOfProcessors)
+      res = execProcesses(cmds, {poStdErrToStdOut, poUsePath, poParentStreams},
+                          gNumberOfProcessors, afterRunEvent=runCb)
     if res != 0:
       if gNumberOfProcessors <= 1:
         rawMessage(errExecutionOfProgramFailed, cmds.join())
-      else:
-        rawMessage(errGenerated,
-                   " execution of an external compiler program failed: " &
-                   cmds.join() & "; " &
-                   "rerun with --parallelBuild:1 to see the error message")
   if optNoLinking notin gGlobalOptions:
     # call the linker:
     var it = PStrEntry(toLink.head)
diff --git a/compiler/pragmas.nim b/compiler/pragmas.nim
index 1c51251fe7..ba05b2792a 100644
--- a/compiler/pragmas.nim
+++ b/compiler/pragmas.nim
@@ -56,7 +56,7 @@ const
     wInheritable, wGensym, wInject, wRequiresInit, wUnchecked, wUnion, wPacked,
     wBorrow, wGcSafe}
   fieldPragmas* = {wImportc, wExportc, wDeprecated, wExtern,
-    wImportCpp, wImportObjC, wError, wGuard}
+    wImportCpp, wImportObjC, wError, wGuard, wBitsize}
   varPragmas* = {wImportc, wExportc, wVolatile, wRegister, wThreadVar, wNodecl,
     wMagic, wHeader, wDeprecated, wCompilerproc, wDynlib, wExtern,
     wImportCpp, wImportObjC, wError, wNoInit, wCompileTime, wGlobal,
@@ -844,6 +844,11 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: int,
         if sym == nil: pragmaLockStmt(c, it)
         elif sym.typ == nil: invalidPragma(it)
         else: sym.typ.lockLevel = pragmaLocks(c, it)
+      of wBitsize:
+        if sym == nil or sym.kind != skField or it.kind != nkExprColonExpr:
+          invalidPragma(it)
+        else:
+          sym.bitsize = expectIntLit(c, it)
       of wGuard:
         if sym == nil or sym.kind notin {skVar, skLet, skField}:
           invalidPragma(it)
diff --git a/compiler/wordrecg.nim b/compiler/wordrecg.nim
index 23f012ea50..d1e5438f3d 100644
--- a/compiler/wordrecg.nim
+++ b/compiler/wordrecg.nim
@@ -82,6 +82,7 @@ type
     wStdIn, wStdOut, wStdErr,
 
     wInOut, wByCopy, wByRef, wOneWay,
+    wBitsize,
 
   TSpecialWords* = set[TSpecialWord]
 
@@ -168,6 +169,7 @@ const
     "stdin", "stdout", "stderr",
 
     "inout", "bycopy", "byref", "oneway",
+    "bitsize",
     ]
 
 proc findStr*(a: openArray[string], s: string): int =
diff --git a/doc/manual/pragmas.txt b/doc/manual/pragmas.txt
index 68a88f865a..f89194c9ad 100644
--- a/doc/manual/pragmas.txt
+++ b/doc/manual/pragmas.txt
@@ -531,6 +531,24 @@ Implementation Specific Pragmas
 This section describes additional pragmas that the current Nim implementation
 supports but which should not be seen as part of the language specification.
 
+Bitsize pragma
+--------------
+
+The ``bitsize`` pragma is for object field members. It declares the field as
+a bitfield in C/C++.
+
+.. code-block:: Nim
+  type
+    mybitfield = object
+      flag {.bitsize:1.}: cuint
+
+generates:
+
+.. code-block:: C
+  struct mybitfield {
+    unsigned int flag:1;
+  };
+
 
 Volatile pragma
 ---------------
diff --git a/examples/filterex.nim b/examples/filterex.nim
index d9bfb67822..0839452544 100644
--- a/examples/filterex.nim
+++ b/examples/filterex.nim
@@ -1,4 +1,4 @@
-#! stdtmpl | standard
+#? stdtmpl | standard
 #proc generateHTMLPage(title, currentTab, content: string,
 #                      tabs: openArray[string]): string =
 #  result = ""
diff --git a/lib/pure/ospaths.nim b/lib/pure/ospaths.nim
index fd28db4438..667ca82d73 100644
--- a/lib/pure/ospaths.nim
+++ b/lib/pure/ospaths.nim
@@ -500,7 +500,7 @@ when defined(nimdoc) and not declared(os):
   proc existsFile(x: string): bool = discard
 
 when declared(getEnv) or defined(nimscript):
-  proc getHomeDir*(): string {.rtl, extern: "nos$1", tags: [ReadEnvEffect].} =
+  proc getHomeDir*(): string {.rtl, extern: "nos$1", tags: [ReadEnvEffect, ReadIOEffect].} =
     ## Returns the home directory of the current user.
     ##
     ## This proc is wrapped by the expandTilde proc for the convenience of
@@ -508,7 +508,7 @@ when declared(getEnv) or defined(nimscript):
     when defined(windows): return string(getEnv("USERPROFILE")) & "\\"
     else: return string(getEnv("HOME")) & "/"
 
-  proc getConfigDir*(): string {.rtl, extern: "nos$1", tags: [ReadEnvEffect].} =
+  proc getConfigDir*(): string {.rtl, extern: "nos$1", tags: [ReadEnvEffect, ReadIOEffect].} =
     ## Returns the config directory of the current user for applications.
     when defined(windows): return string(getEnv("APPDATA")) & "\\"
     else: return string(getEnv("HOME")) & "/.config/"
@@ -519,7 +519,7 @@ when declared(getEnv) or defined(nimscript):
     when defined(windows): return string(getEnv("TEMP")) & "\\"
     else: return "/tmp/"
 
-  proc expandTilde*(path: string): string {.tags: [ReadEnvEffect].} =
+  proc expandTilde*(path: string): string {.tags: [ReadEnvEffect, ReadIOEffect].} =
     ## Expands a path starting with ``~/`` to a full path.
     ##
     ## If `path` starts with the tilde character and is followed by `/` or `\\`
@@ -549,7 +549,7 @@ when declared(getEnv) or defined(nimscript):
           yield substr(s, first, last-1)
           inc(last)
 
-  proc findExe*(exe: string): string {.tags: [ReadDirEffect, ReadEnvEffect].} =
+  proc findExe*(exe: string): string {.tags: [ReadDirEffect, ReadEnvEffect, ReadIOEffect].} =
     ## Searches for `exe` in the current working directory and then
     ## in directories listed in the ``PATH`` environment variable.
     ## Returns "" if the `exe` cannot be found. On DOS-like platforms, `exe`
diff --git a/lib/pure/osproc.nim b/lib/pure/osproc.nim
index bc73f7119d..c23126be91 100644
--- a/lib/pure/osproc.nim
+++ b/lib/pure/osproc.nim
@@ -248,7 +248,8 @@ proc countProcessors*(): int {.rtl, extern: "nosp$1".} =
 proc execProcesses*(cmds: openArray[string],
                     options = {poStdErrToStdOut, poParentStreams},
                     n = countProcessors(),
-                    beforeRunEvent: proc(idx: int) = nil): int
+                    beforeRunEvent: proc(idx: int) = nil,
+                    afterRunEvent: proc(idx: int, p: Process) = nil): int
                     {.rtl, extern: "nosp$1",
                     tags: [ExecIOEffect, TimeEffect, ReadEnvEffect, RootEffect]} =
   ## executes the commands `cmds` in parallel. Creates `n` processes
@@ -278,6 +279,7 @@ proc execProcesses*(cmds: openArray[string],
             err.add("\n")
           echo(err)
         result = max(waitForExit(q[r]), result)
+        if afterRunEvent != nil: afterRunEvent(r, q[r])
         if q[r] != nil: close(q[r])
         if beforeRunEvent != nil:
           beforeRunEvent(i)
@@ -291,6 +293,7 @@ proc execProcesses*(cmds: openArray[string],
           if not running(q[r]):
             #echo(outputStream(q[r]).readLine())
             result = max(waitForExit(q[r]), result)
+            if afterRunEvent != nil: afterRunEvent(r, q[r])
             if q[r] != nil: close(q[r])
             if beforeRunEvent != nil:
               beforeRunEvent(i)
@@ -299,6 +302,7 @@ proc execProcesses*(cmds: openArray[string],
             if i > high(cmds): break
     for j in 0..m-1:
       result = max(waitForExit(q[j]), result)
+      if afterRunEvent != nil: afterRunEvent(j, q[j])
       if q[j] != nil: close(q[j])
   else:
     for i in 0..high(cmds):
@@ -306,6 +310,7 @@ proc execProcesses*(cmds: openArray[string],
         beforeRunEvent(i)
       var p = startProcess(cmds[i], options=options + {poEvalCommand})
       result = max(waitForExit(p), result)
+      if afterRunEvent != nil: afterRunEvent(i, p)
       close(p)
 
 proc select*(readfds: var seq[Process], timeout = 500): int {.benign.}
diff --git a/lib/pure/rationals.nim b/lib/pure/rationals.nim
index 60d09c71ac..7d9241412a 100644
--- a/lib/pure/rationals.nim
+++ b/lib/pure/rationals.nim
@@ -18,8 +18,9 @@ type Rational*[T] = object
   ## a rational number, consisting of a numerator and denominator
   num*, den*: T
 
-proc initRational*[T](num, den: T): Rational[T] =
+proc initRational*[T:SomeInteger](num, den: T): Rational[T] =
   ## Create a new rational number.
+  assert(den != 0, "a denominator of zero value is invalid")
   result.num = num
   result.den = den
 
@@ -33,7 +34,7 @@ proc `$`*[T](x: Rational[T]): string =
   ## Turn a rational number into a string.
   result = $x.num & "/" & $x.den
 
-proc toRational*[T](x: T): Rational[T] =
+proc toRational*[T:SomeInteger](x: T): Rational[T] =
   ## Convert some integer `x` to a rational number.
   result.num = x
   result.den = 1
@@ -47,7 +48,7 @@ proc toInt*[T](x: Rational[T]): int =
   ## `x` does not contain an integer value.
   x.num div x.den
 
-proc reduce*[T](x: var Rational[T]) =
+proc reduce*[T:SomeInteger](x: var Rational[T]) =
   ## Reduce rational `x`.
   let common = gcd(x.num, x.den)
   if x.den > 0:
diff --git a/tests/pragmas/tbitsize.nim b/tests/pragmas/tbitsize.nim
new file mode 100644
index 0000000000..7a44944d24
--- /dev/null
+++ b/tests/pragmas/tbitsize.nim
@@ -0,0 +1,22 @@
+discard """
+ccodeCheck: "\\i @'unsigned int flag:1;' .*"
+"""
+
+type
+  bits* = object
+    flag* {.bitsize: 1.}: cuint
+    opts* {.bitsize: 4.}: cint
+
+var
+  b: bits
+
+assert b.flag == 0
+b.flag = 1
+assert b.flag == 1
+b.flag = 2
+assert b.flag == 0
+
+b.opts = 7
+assert b.opts == 7
+b.opts = 9
+assert b.opts == -7
diff --git a/tests/rational/trat_float.nim b/tests/rational/trat_float.nim
new file mode 100644
index 0000000000..24797c4a01
--- /dev/null
+++ b/tests/rational/trat_float.nim
@@ -0,0 +1,9 @@
+discard """
+  file: "trat_float.nim"
+  line: "9,19"
+  errormsg: '''type mismatch: got'''
+"""
+import rationals
+var
+  # this fails - no floats as num or den
+  r = initRational(1.0'f, 1.0'f)
diff --git a/tests/rational/trat_init.nim b/tests/rational/trat_init.nim
new file mode 100644
index 0000000000..df29ff6e33
--- /dev/null
+++ b/tests/rational/trat_init.nim
@@ -0,0 +1,10 @@
+discard """
+  file: "trat_init.nim"
+  exitcode: "1"
+"""
+import rationals
+var
+  z = Rational[int](num: 0, den: 1)
+  o = initRational(num=1, den=1)
+  a = initRational(1, 2)
+  r = initRational(1, 0)  # this fails - no zero denominator
diff --git a/tests/template/sunset.tmpl b/tests/template/sunset.tmpl
index 6475bac4ec..465b12a5ea 100644
--- a/tests/template/sunset.tmpl
+++ b/tests/template/sunset.tmpl
@@ -1,4 +1,4 @@
-#! stdtmpl
+#? stdtmpl
 #proc sunsetTemplate*(current, ticker, content: string,
 #                     tabs: openarray[array[0..1, string]]): string = 
 #  result = ""
diff --git a/tests/testament/tester.nim b/tests/testament/tester.nim
index 3961f15c40..e52988682b 100644
--- a/tests/testament/tester.nim
+++ b/tests/testament/tester.nim
@@ -213,6 +213,8 @@ proc compilerOutputTests(test: TTest, given: var TSpec, expected: TSpec;
       expectedmsg = expected.nimout
       givenmsg = given.nimout.strip
       nimoutCheck(test, expectedmsg, given)
+  else:
+    givenmsg = given.nimout.strip
   if given.err == reSuccess: inc(r.passed)
   r.addResult(test, expectedmsg, givenmsg, given.err)
 
diff --git a/tools/niminst/buildbat.tmpl b/tools/niminst/buildbat.tmpl
index 2c6a2b5a80..2a8da144d2 100644
--- a/tools/niminst/buildbat.tmpl
+++ b/tools/niminst/buildbat.tmpl
@@ -1,4 +1,4 @@
-#! stdtmpl(subsChar='?') | standard
+#? stdtmpl(subsChar='?') | standard
 #proc generateBuildBatchScript(c: ConfigData, winIndex, cpuIndex: int): string = 
 #  result = "@echo off\nREM Generated by niminst\n"
 SET CC=gcc
diff --git a/tools/niminst/buildsh.tmpl b/tools/niminst/buildsh.tmpl
index 52da351bee..463a1ad527 100644
--- a/tools/niminst/buildsh.tmpl
+++ b/tools/niminst/buildsh.tmpl
@@ -1,4 +1,4 @@
-#! stdtmpl(subsChar='?') | standard
+#? stdtmpl(subsChar='?') | standard
 #proc generateBuildShellScript(c: ConfigData): string = 
 #  result = "#! /bin/sh\n# Generated from niminst\n" &
 #           "# Template is in tools/niminst/buildsh.tmpl\n" &
diff --git a/tools/niminst/deinstall.tmpl b/tools/niminst/deinstall.tmpl
index c4717a2579..7349abcb43 100644
--- a/tools/niminst/deinstall.tmpl
+++ b/tools/niminst/deinstall.tmpl
@@ -1,4 +1,4 @@
-#! stdtmpl(subsChar='?') | standard
+#? stdtmpl(subsChar='?') | standard
 #proc generateDeinstallScript(c: ConfigData): string = 
 #  result = "#! /bin/sh\n# Generated by niminst\n"
 #  var proj = c.name.toLower
diff --git a/tools/niminst/inno.tmpl b/tools/niminst/inno.tmpl
index 4acf0557c8..ef2da8a755 100644
--- a/tools/niminst/inno.tmpl
+++ b/tools/niminst/inno.tmpl
@@ -1,4 +1,4 @@
-#! stdtmpl | standard
+#? stdtmpl | standard
 #proc generateInnoSetup(c: ConfigData): string =
 #  result = ""
 ; Default Template for NimInst
diff --git a/tools/niminst/install.tmpl b/tools/niminst/install.tmpl
index 3ec42c2874..14d88e07df 100644
--- a/tools/niminst/install.tmpl
+++ b/tools/niminst/install.tmpl
@@ -1,4 +1,4 @@
-#! stdtmpl(subsChar = '?') | standard
+#? stdtmpl(subsChar = '?') | standard
 #proc generateInstallScript(c: ConfigData): string = 
 #  result = "#! /bin/sh\n# Generated by niminst\n"
 #  var proj = c.name.toLower
diff --git a/tools/niminst/makefile.tmpl b/tools/niminst/makefile.tmpl
index 8ab3b89d15..6615ddc022 100644
--- a/tools/niminst/makefile.tmpl
+++ b/tools/niminst/makefile.tmpl
@@ -1,4 +1,4 @@
-#! stdtmpl(subsChar='?') | standard
+#? stdtmpl(subsChar='?') | standard
 #proc generateMakefile(c: ConfigData): string = 
 #  result = "# Generated from niminst\n" &
 #           "# Template is in tools/niminst/makefile.tmpl\n" &
diff --git a/tools/niminst/nsis.tmpl b/tools/niminst/nsis.tmpl
index 843a8cf440..abf4623887 100644
--- a/tools/niminst/nsis.tmpl
+++ b/tools/niminst/nsis.tmpl
@@ -1,4 +1,4 @@
-#! stdtmpl(subsChar='?') | standard
+#? stdtmpl(subsChar='?') | standard
 #proc generateNsisSetup(c: ConfigData): string =
 #  result = "; NSIS script generated by niminst\n" &
 #           "; To regenerate run ``niminst nsis`` or ``koch nsis``\n"
diff --git a/web/news.txt b/web/news.txt
index cfa40c65ca..33ceac49e4 100644
--- a/web/news.txt
+++ b/web/news.txt
@@ -108,6 +108,8 @@ News
   - The compiler finally considers symbol binding rules in templates and
     generics for overloaded ``[]``, ``[]=``, ``{}``, ``{}=`` operators
     (issue `#2599 <https://github.com/nim-lang/Nim/issues/2599>`_).
+  - The compiler now supports a `bitsize pragma <docs/manual.html#pragmas-bitsize-pragma>`_
+    for constructing bitfields.
 
 
   Language Additions