diff --git a/Makefile.am b/Makefile.am
index 2cf8e0574..09be93a82 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -444,7 +444,7 @@ libutil_a_SOURCES = \
 # Multi-threading library
 
 libthread_a_SOURCES = \
-	src/thread/Util.hxx \
+	src/thread/Util.cxx src/thread/Util.hxx \
 	src/thread/Name.hxx \
 	src/thread/Slack.hxx \
 	src/thread/Mutex.hxx \
diff --git a/src/thread/Util.cxx b/src/thread/Util.cxx
new file mode 100644
index 000000000..1a01c298b
--- /dev/null
+++ b/src/thread/Util.cxx
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2014-2016 Max Kellermann <max@duempel.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "Util.hxx"
+#include "util/Error.hxx"
+
+#ifdef __linux__
+#include <sched.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#elif defined(WIN32)
+#include <windows.h>
+#endif
+
+#ifdef __linux__
+
+static int
+ioprio_set(int which, int who, int ioprio)
+{
+	return syscall(__NR_ioprio_set, which, who, ioprio);
+}
+
+static void
+ioprio_set_idle()
+{
+	static constexpr int _IOPRIO_WHO_PROCESS = 1;
+	static constexpr int _IOPRIO_CLASS_IDLE = 3;
+	static constexpr int _IOPRIO_CLASS_SHIFT = 13;
+	static constexpr int _IOPRIO_IDLE =
+		(_IOPRIO_CLASS_IDLE << _IOPRIO_CLASS_SHIFT) | 7;
+
+	ioprio_set(_IOPRIO_WHO_PROCESS, 0, _IOPRIO_IDLE);
+}
+
+#endif
+
+void
+SetThreadIdlePriority()
+{
+#ifdef __linux__
+#ifdef SCHED_IDLE
+	static struct sched_param sched_param;
+	sched_setscheduler(0, SCHED_IDLE, &sched_param);
+#endif
+
+	ioprio_set_idle();
+
+#elif defined(WIN32)
+	SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_IDLE);
+#endif
+};
+
+bool
+SetThreadRealtime(Error& error)
+{
+#ifdef __linux__
+	struct sched_param sched_param;
+	sched_param.sched_priority = 50;
+
+	int policy = SCHED_FIFO;
+#ifdef SCHED_RESET_ON_FORK
+	policy |= SCHED_RESET_ON_FORK;
+#endif
+
+	if(sched_setscheduler(0, policy, &sched_param)==0) {
+		return true;
+	} else {
+		error.FormatErrno("sched_setscheduler failed");
+		return false;
+	}
+#else
+	return true; // on non-linux systems, we pretend it worked
+#endif	// __linux__
+};
diff --git a/src/thread/Util.hxx b/src/thread/Util.hxx
index bf9949b52..0f8062c86 100644
--- a/src/thread/Util.hxx
+++ b/src/thread/Util.hxx
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014 Max Kellermann <max@duempel.org>
+ * Copyright (C) 2014-2016 Max Kellermann <max@duempel.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -30,83 +30,20 @@
 #ifndef THREAD_UTIL_HXX
 #define THREAD_UTIL_HXX
 
-#include "util/Error.hxx"
-
-#ifdef __linux__
-#include <sched.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-#elif defined(WIN32)
-#include <windows.h>
-#endif
-
-#ifdef __linux__
-
-static int
-ioprio_set(int which, int who, int ioprio)
-{
-	return syscall(__NR_ioprio_set, which, who, ioprio);
-}
-
-static void
-ioprio_set_idle()
-{
-	static constexpr int _IOPRIO_WHO_PROCESS = 1;
-	static constexpr int _IOPRIO_CLASS_IDLE = 3;
-	static constexpr int _IOPRIO_CLASS_SHIFT = 13;
-	static constexpr int _IOPRIO_IDLE =
-		(_IOPRIO_CLASS_IDLE << _IOPRIO_CLASS_SHIFT) | 7;
-
-	ioprio_set(_IOPRIO_WHO_PROCESS, 0, _IOPRIO_IDLE);
-}
-
-#endif
+class Error;
 
 /**
  * Lower the current thread's priority to "idle" (very low).
  */
-static inline void
-SetThreadIdlePriority()
-{
-#ifdef __linux__
-#ifdef SCHED_IDLE
-	static struct sched_param sched_param;
-	sched_setscheduler(0, SCHED_IDLE, &sched_param);
-#endif
-
-	ioprio_set_idle();
-
-#elif defined(WIN32)
-	SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_IDLE);
-#endif
-};
+void
+SetThreadIdlePriority();
 
 /**
  * Raise the current thread's priority to "real-time" (very high).
  * @param[out]	error	Receives error information on failure
  * @return	true on success (always true on non-linux systems)
  */
-static inline bool
-SetThreadRealtime(Error& error)
-{
-#ifdef __linux__
-	struct sched_param sched_param;
-	sched_param.sched_priority = 50;
-
-	int policy = SCHED_FIFO;
-#ifdef SCHED_RESET_ON_FORK
-	policy |= SCHED_RESET_ON_FORK;
-#endif
-
-	if(sched_setscheduler(0, policy, &sched_param)==0) {
-		return true;
-	} else {
-		error.FormatErrno("sched_setscheduler failed");
-		return false;
-	}
-#else
-	return true; // on non-linux systems, we pretend it worked
-#endif	// __linux__
-};
+bool
+SetThreadRealtime(Error &error);
 
 #endif