diff --git a/trunk/src/core/srs_core.cpp b/trunk/src/core/srs_core.cpp
index 96db00bc9..8f409f4ec 100644
--- a/trunk/src/core/srs_core.cpp
+++ b/trunk/src/core/srs_core.cpp
@@ -37,17 +37,21 @@ _SrsContextId::_SrsContextId(const _SrsContextId& cp)
     v_ = cp.v_;
 }
 
-const char* _SrsContextId::c_str()
+_SrsContextId::~_SrsContextId()
+{
+}
+
+const char* _SrsContextId::c_str() const
 {
     return v_.c_str();
 }
 
-bool _SrsContextId::empty()
+bool _SrsContextId::empty() const
 {
     return v_.empty();
 }
 
-int _SrsContextId::compare(const _SrsContextId& to)
+int _SrsContextId::compare(const _SrsContextId& to) const
 {
     return v_.compare(to.v_);
 }
diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index 65da94cd0..a68549697 100644
--- a/trunk/src/core/srs_core.hpp
+++ b/trunk/src/core/srs_core.hpp
@@ -125,14 +125,15 @@ public:
     _SrsContextId();
     _SrsContextId(std::string v);
     _SrsContextId(const _SrsContextId& cp);
+    virtual ~_SrsContextId();
 public:
-    const char* c_str();
-    bool empty();
+    const char* c_str() const;
+    bool empty() const;
     // Compare the two context id. @see http://www.cplusplus.com/reference/string/string/compare/
     //      0	They compare equal
     //      <0	Either the value of the first character that does not match is lower in the compared string, or all compared characters match but the compared string is shorter.
     //      >0	Either the value of the first character that does not match is greater in the compared string, or all compared characters match but the compared string is longer.
-    int compare(const _SrsContextId& to);
+    int compare(const _SrsContextId& to) const;
 };
 typedef _SrsContextId SrsContextId;
 #else