diff --git a/tools/bifcl/include/module_util.h b/tools/bifcl/include/module_util.h
index fa5f24964f..7b85f81c23 100644
--- a/tools/bifcl/include/module_util.h
+++ b/tools/bifcl/include/module_util.h
@@ -6,14 +6,12 @@
 
 #include <string>
 
-using namespace std;
-
 static const char* GLOBAL_MODULE_NAME = "GLOBAL";
 
-extern string extract_module_name(const char* name);
-extern string extract_var_name(const char* name);
-extern string normalized_module_name(const char* module_name); // w/o ::
+extern std::string extract_module_name(const char* name);
+extern std::string extract_var_name(const char* name);
+extern std::string normalized_module_name(const char* module_name); // w/o ::
 
 // Concatenates module_name::var_name unless var_name is already fully
 // qualified, in which case it is returned unmodified.
-extern string make_full_var_name(const char* module_name, const char* var_name);
+extern std::string make_full_var_name(const char* module_name, const char* var_name);
diff --git a/tools/bifcl/module_util.cc b/tools/bifcl/module_util.cc
index 27e1141fde..b3997cd1d6 100644
--- a/tools/bifcl/module_util.cc
+++ b/tools/bifcl/module_util.cc
@@ -3,9 +3,11 @@
 
 #include "module_util.h"
 
-#include <string.h>
+#include <cstring>
 #include <string>
 
+using namespace std;
+
 static int streq(const char* s1, const char* s2) { return ! strcmp(s1, s2); }
 
 // Returns it without trailing "::".
@@ -36,7 +38,7 @@ string extract_var_name(const char* name) {
 
 string normalized_module_name(const char* module_name) {
     int mod_len;
-    if ( (mod_len = strlen(module_name)) >= 2 && streq(module_name + mod_len - 2, "::") )
+    if ( mod_len = strlen(module_name); mod_len >= 2 && streq(module_name + mod_len - 2, "::") )
         mod_len -= 2;
 
     return string(module_name, mod_len);