diff --git a/include/sta/Sta.hh b/include/sta/Sta.hh
index ed1c6c47..718f97ae 100644
--- a/include/sta/Sta.hh
+++ b/include/sta/Sta.hh
@@ -1297,13 +1297,13 @@ public:
   void clkPinsInvalid(const Mode *mode);
   // The following functions assume ensureClkNetwork() has been called.
   bool isClock(const Pin *pin,
-               const Mode *mode) const;
+               const Mode *mode);
   bool isClock(const Net *net,
-               const Mode *mode) const;
+               const Mode *mode);
   bool isIdealClock(const Pin *pin,
-                    const Mode *mode) const;
+                    const Mode *mode);
   bool isPropagatedClock(const Pin *pin,
-                         const Mode *mode) const;
+                         const Mode *mode);
   const PinSet *pins(const Clock *clk,
                      const Mode *mode);
 
diff --git a/search/Search.i b/search/Search.i
index 8978d530..67d84876 100644
--- a/search/Search.i
+++ b/search/Search.i
@@ -335,6 +335,15 @@ slow_drivers(int count)
   return Sta::sta()->slowDrivers(count);
 }
 
+bool
+is_ideal_clock(const Pin *pin)
+{
+  Sta *sta = Sta::sta();
+  const Mode *mode = sta->cmdMode();
+  sta->ensureClkNetwork();
+  return sta->isIdealClock(pin, mode);
+}
+
 ////////////////////////////////////////////////////////////////
 
 PathEndSeq
diff --git a/search/Sta.cc b/search/Sta.cc
index fa1c3bb4..2d91a4f4 100644
--- a/search/Sta.cc
+++ b/search/Sta.cc
@@ -6054,28 +6054,31 @@ Sta::ensureClkNetwork(const Mode *mode)
 
 bool
 Sta::isClock(const Pin *pin,
-             const Mode *mode) const
+             const Mode *mode)
 {
+  ensureClkNetwork(mode);
   return mode->clkNetwork()->isClock(pin);
 }
 
 bool
 Sta::isClock(const Net *net,
-             const Mode *mode) const
+             const Mode *mode)
 {
+  ensureClkNetwork(mode);
   return mode->clkNetwork()->isClock(net);
 }
 
 bool
 Sta::isIdealClock(const Pin *pin,
-                  const Mode *mode) const
+                  const Mode *mode)
 {
+  ensureClkNetwork(mode);
   return mode->clkNetwork()->isIdealClock(pin);
 }
 
 bool
 Sta::isPropagatedClock(const Pin *pin,
-                       const Mode *mode) const
+                       const Mode *mode)
 {
   return mode->clkNetwork()->isPropagatedClock(pin);
 }
@@ -6084,12 +6087,14 @@ const PinSet *
 Sta::pins(const Clock *clk,
           const Mode *mode)
 {
+  ensureClkNetwork(mode);
   return mode->clkNetwork()->pins(clk);
 }
 
 void
 Sta::clkPinsInvalid(const Mode *mode)
 {
+  ensureClkNetwork(mode);
   mode->clkNetwork()->clkPinsInvalid();
 }