diff --git a/easylogger/src/elog_buf.c b/easylogger/src/elog_buf.c
index b4a8f10..e4a3199 100644
--- a/easylogger/src/elog_buf.c
+++ b/easylogger/src/elog_buf.c
@@ -82,14 +82,16 @@ void elog_buf_output(const char *log, size_t size) {
  * flush all buffered logs to output device
  */
 void elog_flush(void) {
-    /* lock output */
-    elog_output_lock();
-    /* output log */
-    elog_port_output(log_buf, buf_write_size);
-    /* reset write index */
-    buf_write_size = 0;
-    /* unlock output */
-    elog_output_unlock();
+    if(buf_write_size){
+        /* lock output */
+        elog_output_lock();
+        /* output log */
+        elog_port_output(log_buf, buf_write_size);
+        /* reset write index */
+        buf_write_size = 0;
+        /* unlock output */
+        elog_output_unlock();
+    }
 }
 
 /**