From abf511245a4c69af5745ba99e6e69527a347dbf9 Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Fri, 8 Aug 2014 09:54:43 +0200
Subject: [PATCH] nice error message

---
 lib/pure/concurrency/threadpool.nim | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/pure/concurrency/threadpool.nim b/lib/pure/concurrency/threadpool.nim
index 3c636d1ce7..e0a2ac6782 100644
--- a/lib/pure/concurrency/threadpool.nim
+++ b/lib/pure/concurrency/threadpool.nim
@@ -9,6 +9,9 @@
 
 ## Implements Nimrod's 'spawn'.
 
+when not compileOption("threads"):
+  {.error: "Threadpool requires --threads:on option.".}
+
 import cpuinfo, cpuload, locks
 
 {.push stackTrace:off.}