diff --git a/trunk/research/st/srs.c b/trunk/research/st/srs.c
index 3d10d24ff..5e25888b1 100644
--- a/trunk/research/st/srs.c
+++ b/trunk/research/st/srs.c
@@ -5,54 +5,88 @@
 
 #define srs_trace(msg, ...)   printf(msg, ##__VA_ARGS__);printf("\n")
 
-st_mutex_t start = NULL;
-st_cond_t cond = NULL;
-st_mutex_t mutex = NULL;
+st_mutex_t sync_start = NULL;
+st_cond_t sync_cond = NULL;
+st_mutex_t sync_mutex = NULL;
 
-void* master(void* arg)
+void* sync_master(void* arg)
 {
-    // wait for main to start this thread.
-    st_mutex_lock(start);
-    st_mutex_unlock(start);
+    // wait for main to sync_start this thread.
+    st_mutex_lock(sync_start);
+    st_mutex_unlock(sync_start);
     
     st_usleep(100 * 1000);
-    st_cond_signal(cond);
+    st_cond_signal(sync_cond);
     
-    st_mutex_lock(mutex);
+    st_mutex_lock(sync_mutex);
     srs_trace("2. st mutex is ok");
-    st_mutex_unlock(mutex);
+    st_mutex_unlock(sync_mutex);
     
     st_usleep(100 * 1000);
     srs_trace("3. st thread is ok");
-    st_cond_signal(cond);
+    st_cond_signal(sync_cond);
     
     return NULL;
 }
 
-void* slave(void* arg)
+void* sync_slave(void* arg)
 {
     // lock mutex to control thread.
-    st_mutex_lock(mutex);
+    st_mutex_lock(sync_mutex);
     
-    // wait for main to start this thread.
-    st_mutex_lock(start);
-    st_mutex_unlock(start);
+    // wait for main to sync_start this thread.
+    st_mutex_lock(sync_start);
+    st_mutex_unlock(sync_start);
     
     // wait thread to ready.
-    st_cond_wait(cond);
+    st_cond_wait(sync_cond);
     srs_trace("1. st cond is ok");
     
     // release mutex to control thread
     st_usleep(100 * 1000);
-    st_mutex_unlock(mutex);
+    st_mutex_unlock(sync_mutex);
     
     // wait thread to exit.
-    st_cond_wait(cond);
+    st_cond_wait(sync_cond);
     srs_trace("4. st is ok");
     
     return NULL;
 }
 
+int sync_test()
+{
+    if ((sync_start = st_mutex_new()) == NULL) {
+        srs_trace("st_mutex_new sync_start failed");
+        return -1;
+    }
+    st_mutex_lock(sync_start);
+
+    if ((sync_cond = st_cond_new()) == NULL) {
+        srs_trace("st_cond_new cond failed");
+        return -1;
+    }
+    
+    if ((sync_mutex = st_mutex_new()) == NULL) {
+        srs_trace("st_mutex_new mutex failed");
+        return -1;
+    }
+    
+    if (!st_thread_create(sync_master, NULL, 0, 0)) {
+        srs_trace("st_thread_create failed");
+        return -1;
+    }
+    
+    if (!st_thread_create(sync_slave, NULL, 0, 0)) {
+        srs_trace("st_thread_create failed");
+        return -1;
+    }
+    
+    // run all threads.
+    st_mutex_unlock(sync_start);
+    
+    return 0;
+}
+
 int main(int argc, char** argv)
 {
     if (st_set_eventsys(ST_EVENTSYS_ALT) < 0) {
@@ -64,43 +98,15 @@ int main(int argc, char** argv)
         srs_trace("st_init failed");
         return -1;
     }
-
-    if ((start = st_mutex_new()) == NULL) {
-        srs_trace("st_mutex_new start failed");
-        return -1;
-    }
-    st_mutex_lock(start);
-
-    if ((cond = st_cond_new()) == NULL) {
-        srs_trace("st_cond_new cond failed");
-        return -1;
-    }
     
-    if ((mutex = st_mutex_new()) == NULL) {
-        srs_trace("st_mutex_new mutex failed");
+    if (sync_test() < 0) {
+        srs_trace("sync_test failed");
         return -1;
     }
     
-    if (!st_thread_create(master, NULL, 0, 0)) {
-        srs_trace("st_thread_create failed");
-        return -1;
-    }
-    
-    if (!st_thread_create(slave, NULL, 0, 0)) {
-        srs_trace("st_thread_create failed");
-        return -1;
-    }
-    
-    // run all threads.
-    st_mutex_unlock(start);
-    
     // cleanup.
     st_thread_exit(NULL);
     
-    st_mutex_destroy(start);
-    st_cond_destroy(cond);
-    st_mutex_destroy(mutex);
-    
     return 0;
 }