diff --git a/include/string_view.h b/include/string_view.h
index 4076d52..7080ce5 100644
--- a/include/string_view.h
+++ b/include/string_view.h
@@ -82,9 +82,9 @@ template<class T, class SizeType, const T Sentinel>
 array_view<T, dynamic_range> ensure_sentinel(const T* seq, SizeType max = std::numeric_limits<SizeType>::max())
 {
     auto cur = seq;
-    while ((cur - seq) < max && *cur != Sentinel) ++cur;
+    while (SizeType(cur - seq) < max && *cur != Sentinel) ++cur;
     fail_fast_assert(*cur == Sentinel);
-    return{ seq, cur - seq };
+    return{ seq, SizeType(cur - seq) };
 }
 
 
@@ -96,7 +96,7 @@ array_view<T, dynamic_range> ensure_sentinel(const T* seq, SizeType max = std::n
 template<class T>
 inline basic_string_view<T, dynamic_range> ensure_z(T* const & sz, size_t max = std::numeric_limits<size_t>::max())
 {
-    return ensure_sentinel<0>(sz, max);
+    return ensure_sentinel<T, size_t, 0>(sz, max);
 }
 
 // TODO (neilmac) there is probably a better template-magic way to get the const and non-const overloads to share an implementation
diff --git a/tests/string_view_tests.cpp b/tests/string_view_tests.cpp
index fb57845..e553ccd 100644
--- a/tests/string_view_tests.cpp
+++ b/tests/string_view_tests.cpp
@@ -79,6 +79,14 @@ SUITE(string_view_tests)
         }
 	}
 
+    TEST(TestConstructFromConstCharPointer)
+    {
+        const char* s = "Hello";
+        cstring_view<> v = ensure_z(s);
+        CHECK(v.length() == 5);
+        CHECK(v.used_length() == v.length());
+    }
+
     TEST(TestConversionToConst)
     {
         char stack_string[] = "Hello";