From 4b2f9e78fcaf07fc81033c31b0127857b10efc07 Mon Sep 17 00:00:00 2001
From: Vadim Pisarevsky <no@email>
Date: Tue, 26 Apr 2011 12:20:42 +0000
Subject: [PATCH] fixed repeated allocation of RNG on each theRNG() call
 (thanks to barjenbr for the patch)

---
 modules/core/src/rand.cpp | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/modules/core/src/rand.cpp b/modules/core/src/rand.cpp
index f0701e82e5..d10e1377eb 100644
--- a/modules/core/src/rand.cpp
+++ b/modules/core/src/rand.cpp
@@ -689,19 +689,22 @@ RNG& theRNG()
 #else
 
 static pthread_key_t tlsRNGKey = 0;
+static pthread_once_t tlsRNGKeyOnce = PTHREAD_ONCE_INIT;
 
 static void deleteRNG(void* data)
 {
     delete (RNG*)data;
 }
 
+static void makeRNGKey()
+{
+	int errcode = pthread_key_create(&tlsRNGKey, deleteRNG);
+	CV_Assert(errcode == 0);
+}
+
 RNG& theRNG()
 {
-    if( !tlsRNGKey )
-    {
-        int errcode = pthread_key_create(&tlsRNGKey, deleteRNG);
-        CV_Assert(errcode == 0);
-    }
+    pthread_once(&tlsRNGKeyOnce, makeRNGKey);
     RNG* rng = (RNG*)pthread_getspecific(tlsRNGKey);
     if( !rng )
     {