diff --git a/src/V3Error.h b/src/V3Error.h
index 79088bee1..72790376f 100644
--- a/src/V3Error.h
+++ b/src/V3Error.h
@@ -24,6 +24,9 @@
 #include "config_build.h"
 #include "verilatedos.h"
 
+// Limited V3 headers here - this is a base class for Vlc etc
+#include "V3String.h"
+
 #include <bitset>
 #include <cassert>
 #include <deque>
@@ -345,25 +348,4 @@ inline void v3errorEndFatal(std::ostringstream& sstr) {
 
 //----------------------------------------------------------------------
 
-template <class T> std::string cvtToStr(const T& t) {
-    std::ostringstream os; os<<t; return os.str();
-}
-template <class T> std::string cvtToHex(const T* tp) {
-    std::ostringstream os; os<<static_cast<const void*>(tp); return os.str();
-}
-
-inline uint32_t cvtToHash(const void* vp) {
-    // We can shove a 64 bit pointer into a 32 bit bucket
-    // On 32-bit systems, lower is always 0, but who cares?
-    union { const void* up; struct {uint32_t upper; uint32_t lower;} l;} u;
-    u.l.upper = 0; u.l.lower = 0; u.up = vp;
-    return u.l.upper^u.l.lower;
-}
-
-inline string ucfirst(const string& text) {
-    string out = text;
-    out[0] = toupper(out[0]);
-    return out;
-}
-
 #endif  // Guard
diff --git a/src/V3Os.cpp b/src/V3Os.cpp
index 97350aad4..2d892153a 100644
--- a/src/V3Os.cpp
+++ b/src/V3Os.cpp
@@ -21,6 +21,7 @@
 #include "config_build.h"
 #include "verilatedos.h"
 
+// Limited V3 headers here - this is a base class for Vlc etc
 #include "V3Global.h"
 #include "V3String.h"
 #include "V3Os.h"
diff --git a/src/V3Os.h b/src/V3Os.h
index fbe5df9d2..753a21b40 100644
--- a/src/V3Os.h
+++ b/src/V3Os.h
@@ -24,6 +24,7 @@
 #include "config_build.h"
 #include "verilatedos.h"
 
+// Limited V3 headers here - this is a base class for Vlc etc
 #include "V3Error.h"
 
 //============================================================================
diff --git a/src/V3String.cpp b/src/V3String.cpp
index 93afb60f7..bd0761b80 100644
--- a/src/V3String.cpp
+++ b/src/V3String.cpp
@@ -21,7 +21,7 @@
 #include "config_build.h"
 #include "verilatedos.h"
 
-#include "V3Global.h"
+// Limited V3 headers here - this is a base class for Vlc etc
 #include "V3String.h"
 #include "V3Error.h"
 
diff --git a/src/V3String.h b/src/V3String.h
index b192b10cb..573d93855 100644
--- a/src/V3String.h
+++ b/src/V3String.h
@@ -24,7 +24,35 @@
 #include "config_build.h"
 #include "verilatedos.h"
 
+// No V3 headers here - this is a base class for Vlc etc
+
 #include <string>
+#include <sstream>
+#include <vector>
+
+//######################################################################
+// Global string-related functions
+
+template <class T> std::string cvtToStr(const T& t) {
+    std::ostringstream os; os<<t; return os.str();
+}
+template <class T> std::string cvtToHex(const T* tp) {
+    std::ostringstream os; os<<static_cast<const void*>(tp); return os.str();
+}
+
+inline uint32_t cvtToHash(const void* vp) {
+    // We can shove a 64 bit pointer into a 32 bit bucket
+    // On 32-bit systems, lower is always 0, but who cares?
+    union { const void* up; struct {uint32_t upper; uint32_t lower;} l;} u;
+    u.l.upper = 0; u.l.lower = 0; u.up = vp;
+    return u.l.upper^u.l.lower;
+}
+
+inline string ucfirst(const string& text) {
+    string out = text;
+    out[0] = toupper(out[0]);
+    return out;
+}
 
 //######################################################################
 // VString - String manipulation