diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.cpp b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.cpp
index c71c42ac..20b967b4 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.cpp
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.cpp
@@ -931,7 +931,7 @@ void IPhreeqc::SetBasicCallback(double (*fcn)(double x1, double x2, const char *
 	this->PhreeqcPtr->register_basic_callback(fcn, cookie1);
 }
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
-void IPhreeqc::SetBasicFortranCallback(double (*fcn)(double *x1, double *x2, char *str, size_t l))
+void IPhreeqc::SetBasicFortranCallback(double (*fcn)(double *x1, double *x2, const char *str, size_t l))
 {
 	this->PhreeqcPtr->register_fortran_basic_callback(fcn);
 }
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.h b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.h
index 62d99029..6be24c24 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.h
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.h
@@ -1711,7 +1711,7 @@ Headings
  *  @include ic
  */
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
-	IPQ_DLL_EXPORT IPQ_RESULT  SetBasicFortranCallback(int id, double (*fcn)(double *x1, double *x2, char *str, size_t l));
+	IPQ_DLL_EXPORT IPQ_RESULT  SetBasicFortranCallback(int id, double (*fcn)(double *x1, double *x2, const char *str, size_t l));
 #else
 	IPQ_DLL_EXPORT IPQ_RESULT  SetBasicFortranCallback(int id, double (*fcn)(double *x1, double *x2, const char *str, int l));
 #endif
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.hpp b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.hpp
index c79957b5..036b14ca 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.hpp
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc.hpp
@@ -718,7 +718,7 @@ class IPQ_DLL_EXPORT IPhreeqc : public PHRQ_io
 	 *  @see                    SetBasicCallback
 	 */
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
-	void                     SetBasicFortranCallback(double (*fcn)(double *x1, double *x2, char *str, size_t l));
+	void                     SetBasicFortranCallback(double (*fcn)(double *x1, double *x2, const char *str, size_t l));
 #else
 	void                     SetBasicFortranCallback(double (*fcn)(double *x1, double *x2, const char *str, int l));
 #endif
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqcLib.cpp b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqcLib.cpp
index b57755ab..d0a3f0ba 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqcLib.cpp
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqcLib.cpp
@@ -802,7 +802,7 @@ SetBasicCallback(int id, double (*fcn)(double x1, double x2, const char *str, vo
 #if !defined(R_SO)
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
 IPQ_RESULT
-SetBasicFortranCallback(int id, double (*fcn)(double *x1, double *x2, char *str, size_t l))
+SetBasicFortranCallback(int id, double (*fcn)(double *x1, double *x2, const char *str, size_t l))
 {
 	IPhreeqc* IPhreeqcPtr = IPhreeqcLib::GetInstance(id);
 	if (IPhreeqcPtr)
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc_interface_F.cpp b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc_interface_F.cpp
index e25590fb..4063d748 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc_interface_F.cpp
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc_interface_F.cpp
@@ -414,7 +414,7 @@ RunStringF(int *id, char* input)
 }
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
 IPQ_RESULT
-SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, char *str, size_t l))
+SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, const char *str, size_t l))
 {
 	return ::SetBasicFortranCallback(*id, fcn);
 }
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc_interface_F.h b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc_interface_F.h
index d3fe29ec..3e77604f 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc_interface_F.h
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/IPhreeqc_interface_F.h
@@ -133,7 +133,7 @@ extern "C" {
   IPQ_DLL_EXPORT int        RunFileF(int *id, char* filename);
   IPQ_DLL_EXPORT int        RunStringF(int *id, char* input);
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
-  IPQ_DLL_EXPORT IPQ_RESULT SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, char *str, size_t l));
+  IPQ_DLL_EXPORT IPQ_RESULT SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, const char *str, size_t l));
 #else
   IPQ_DLL_EXPORT IPQ_RESULT SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, const char *str, int l));
 #endif
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fimpl.h b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fimpl.h
index de9eb214..eddf5a45 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fimpl.h
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fimpl.h
@@ -208,7 +208,7 @@ IPQ_DLL_EXPORT int  IPQ_DECL IPQ_CASE_UND(runstring, RUNSTRING, runstring_, RUNS
 {
 	return RunStringF(id, input, len);
 }
-IPQ_DLL_EXPORT int  IPQ_DECL IPQ_CASE_UND(setbasicfortrancallback, SETBASICFORTRANCALLBACK, setbasicfortrancallback_, SETBASICFORTRANCALLBACK_)(int *id, double (*fcn)(double *x1, double *x2, char *str, size_t l))
+IPQ_DLL_EXPORT int  IPQ_DECL IPQ_CASE_UND(setbasicfortrancallback, SETBASICFORTRANCALLBACK, setbasicfortrancallback_, SETBASICFORTRANCALLBACK_)(int *id, double (*fcn)(double *x1, double *x2, const char *str, size_t l))
 {
 	return SetBasicFortranCallbackF(id, fcn);
 }
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fwrap.cpp b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fwrap.cpp
index bdec8e5a..6903c4f8 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fwrap.cpp
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fwrap.cpp
@@ -482,7 +482,7 @@ RunStringF(int *id, char* input, size_t input_length)
 }
 
 IPQ_RESULT
-SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, char *str, size_t l))
+SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, const char *str, size_t l))
 {
 	return ::SetBasicFortranCallback(*id, fcn);
 }
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fwrap.h b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fwrap.h
index c95758d0..b4449f30 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fwrap.h
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/fwrap.h
@@ -135,7 +135,7 @@ extern "C" {
   int        RunAccumulatedF(int *id);
   int        RunFileF(int *id, char* filename, size_t filename_length);
   int        RunStringF(int *id, char* input, size_t input_length);
-  IPQ_RESULT SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, char *str, size_t l));
+  IPQ_RESULT SetBasicFortranCallbackF(int *id, double (*fcn)(double *x1, double *x2, const char *str, size_t l));
   IPQ_RESULT SetCurrentSelectedOutputUserNumberF(int *id, int *n);
   IPQ_RESULT SetDumpFileNameF(int *id, char* fname, size_t fname_length);
   IPQ_RESULT SetDumpFileOnF(int *id, int* dump_on);
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/Phreeqc.h b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/Phreeqc.h
index 5607f2bc..ddff8262 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/Phreeqc.h
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/Phreeqc.h
@@ -93,13 +93,13 @@ class Phreeqc
 	int basic_run(char* commands, void* lnbase, void* vbase, void* lpbase);
 	void basic_free(void);
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
-	double basic_callback(double x1, double x2, char* str);
+	double basic_callback(double x1, double x2, const char* str);
 #else
 	double basic_callback(double x1, double x2, const char* str);
 #endif
 	void register_basic_callback(double (*fcn)(double x1, double x2, const char* str, void* cookie), void* cookie1);
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
-	void register_fortran_basic_callback(double (*fcn)(double* x1, double* x2, char* str, size_t l));
+	void register_fortran_basic_callback(double (*fcn)(double* x1, double* x2, const char* str, size_t l));
 #else
 	void register_fortran_basic_callback(double (*fcn)(double* x1, double* x2, const char* str, int l));
 #endif
@@ -1661,7 +1661,7 @@ class Phreeqc
 	double (*basic_callback_ptr) (double x1, double x2, const char* str, void* cookie);
 	void* basic_callback_cookie;
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
-	double (*basic_fortran_callback_ptr) (double* x1, double* x2, char* str, size_t l);
+	double (*basic_fortran_callback_ptr) (double* x1, double* x2, const char* str, size_t l);
 #else
 	double (*basic_fortran_callback_ptr) (double* x1, double* x2, const char* str, int l);
 #endif
diff --git a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/basicsubs.cpp b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/basicsubs.cpp
index d49141da..c92e8c30 100644
--- a/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/basicsubs.cpp
+++ b/src/phast/PhreeqcRM/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/basicsubs.cpp
@@ -4242,7 +4242,7 @@ basic_callback(double x1, double x2, const char * str)
 
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
 double Phreeqc::
-basic_callback(double x1, double x2, char * str)
+basic_callback(double x1, double x2, const char * str)
 #else
 double Phreeqc::
 basic_callback(double x1, double x2, const char * str)
@@ -4253,7 +4253,7 @@ basic_callback(double x1, double x2, const char * str)
 
 	if (basic_callback_ptr != NULL)
 	{
-		return (*basic_callback_ptr) (x1, x2, (const char *) str, basic_callback_cookie);
+		return (*basic_callback_ptr) (x1, x2, str, basic_callback_cookie);
 	}
 	if (basic_fortran_callback_ptr != NULL)
 	{
@@ -4274,7 +4274,7 @@ Phreeqc::register_basic_callback(double (*fcn)(double x1, double x2, const char
 }
 #ifdef IPHREEQC_NO_FORTRAN_MODULE
 void 
-Phreeqc::register_fortran_basic_callback(double ( *fcn)(double *x1, double *x2, char *str, size_t l))
+Phreeqc::register_fortran_basic_callback(double ( *fcn)(double *x1, double *x2, const char *str, size_t l))
 {
 	this->basic_fortran_callback_ptr = fcn;
 }