diff --git a/utils/tex2rtf/src/tex2any.cpp b/utils/tex2rtf/src/tex2any.cpp
index 3add6ea1b9..b86f28a724 100644
--- a/utils/tex2rtf/src/tex2any.cpp
+++ b/utils/tex2rtf/src/tex2any.cpp
@@ -243,7 +243,7 @@ CustomMacro::~CustomMacro()
         delete [] macroBody;
 }
 
-void TexOutput(char *s, bool ordinaryText)
+void TexOutput(const char *s, bool ordinaryText)
 {
   int len = strlen(s);
 
diff --git a/utils/tex2rtf/src/tex2any.h b/utils/tex2rtf/src/tex2any.h
index 259b1d5882..0fc16cd94e 100644
--- a/utils/tex2rtf/src/tex2any.h
+++ b/utils/tex2rtf/src/tex2any.h
@@ -159,7 +159,7 @@ extern FILE *CurrentOutput2;
 void AddMacroDef(int the_id, const char *name, int n, bool ignore = FALSE, bool forbidden = FALSE);
 void TexInitialize(int bufSize);
 void TexCleanUp(void);
-void TexOutput(char *s, bool ordinaryText = FALSE);
+void TexOutput(const char *s, bool ordinaryText = FALSE);
 char *GetArgData(TexChunk *chunk);
 char *GetArgData(void);             // Get the string for the current argument
 int GetNoArgs(void);                // Get the number of arguments for the current macro