diff --git a/cwCommonImpl.cpp b/cwCommonImpl.cpp
index 2662132..b7aed68 100644
--- a/cwCommonImpl.cpp
+++ b/cwCommonImpl.cpp
@@ -28,9 +28,11 @@ const char* cw::idToLabel( const idLabelPair_t* array, unsigned id, unsigned eol
 unsigned cw::labelToId( const idLabelPair_t* array, const char* label, unsigned eolId )
 {
   const idLabelPair_t* p = array;
-  for(; p->id != eolId; ++p)
-    if( std::strcmp(label,p->label) == 0 )
-      return p->id;
+
+  if( label != nullptr )
+    for(; p->id != eolId; ++p)
+      if( std::strcmp(label,p->label) == 0 )
+        return p->id;
 
   return eolId;
 }
diff --git a/cwCommonImpl.h b/cwCommonImpl.h
index 0444dbd..438e948 100644
--- a/cwCommonImpl.h
+++ b/cwCommonImpl.h
@@ -17,6 +17,7 @@
 #include <atomic>
 #include <cstdint>
 #include <cmath>
+#include <cctype>
 #include <complex>
 #include <type_traits>
 
@@ -151,7 +152,7 @@ namespace cw
     cwAssert( h.p != nullptr );
     return h.p;
   }
-
+  
   typedef struct idLabelPair_str
   {
     unsigned    id;