the first argument to Bond::extract() should be `const char *` not `char *`.

src/CLASS2/bond_class2.cpp

@@ -224,7 +224,7 @@ double BondClass2::single(int type, double rsq, int /*i*/, int /*j*/, double &ff
 
 /* ---------------------------------------------------------------------- */
 
-void *BondClass2::extract( char *str, int &dim )
+void *BondClass2::extract(const char *str, int &dim)
 {
   dim = 1;
   if (strcmp(str,"r0")==0) return (void*) r0;

src/CLASS2/bond_class2.h

@@ -35,7 +35,7 @@ class BondClass2 : public Bond {
   virtual void read_restart(FILE *);
   void write_data(FILE *);
   double single(int, double, int, int, double &);
-  virtual void *extract(char *, int &);
+  virtual void *extract(const char *, int &);
 
  protected:
   double *r0,*k2,*k3,*k4;

src/MOLECULE/bond_fene.cpp

@@ -276,7 +276,7 @@ double BondFENE::single(int type, double rsq, int /*i*/, int /*j*/,
 
 /* ---------------------------------------------------------------------- */
 
-void *BondFENE::extract( char *str, int &dim )
+void *BondFENE::extract(const char *str, int &dim)
 {
   dim = 1;
   if (strcmp(str,"kappa")==0) return (void*) k;

src/MOLECULE/bond_fene.h

@@ -36,7 +36,7 @@ class BondFENE : public Bond {
   void read_restart(FILE *);
   void write_data(FILE *);
   double single(int, double, int, int, double &);
-  virtual void *extract(char *, int &);
+  virtual void *extract(const char *, int &);
 
  protected:
   double TWO_1_3;

src/MOLECULE/bond_gromos.cpp

@@ -189,7 +189,7 @@ void BondGromos::write_data(FILE *fp)
 /* ---------------------------------------------------------------------- */
 
 double BondGromos::single(int type, double rsq, int /*i*/, int /*j*/,
-                        double &fforce)
+                          double &fforce)
 {
   double dr = rsq - r0[type]*r0[type];
   fforce = -4.0*k[type] * dr;
@@ -199,7 +199,7 @@ double BondGromos::single(int type, double rsq, int /*i*/, int /*j*/,
 /* ----------------------------------------------------------------------
     Return ptr to internal members upon request.
 ------------------------------------------------------------------------ */
-void *BondGromos::extract( char *str, int &dim )
+void *BondGromos::extract(const char *str, int &dim)
 {
   dim = 1;
   if (strcmp(str,"kappa")==0) return (void*) k;

src/MOLECULE/bond_gromos.h

@@ -35,7 +35,7 @@ class BondGromos : public Bond {
   void read_restart(FILE *);
   void write_data(FILE *);
   double single(int, double, int, int, double &);
-  virtual void *extract(char *, int &);
+  virtual void *extract(const char *, int &);
 
  protected:
   double *k,*r0;

src/MOLECULE/bond_harmonic.cpp

@@ -190,7 +190,7 @@ void BondHarmonic::write_data(FILE *fp)
 /* ---------------------------------------------------------------------- */
 
 double BondHarmonic::single(int type, double rsq, int /*i*/, int /*j*/,
-                        double &fforce)
+                            double &fforce)
 {
   double r = sqrt(rsq);
   double dr = r - r0[type];
@@ -203,7 +203,7 @@ double BondHarmonic::single(int type, double rsq, int /*i*/, int /*j*/,
 /* ----------------------------------------------------------------------
     Return ptr to internal members upon request.
 ------------------------------------------------------------------------ */
-void *BondHarmonic::extract( char *str, int &dim )
+void *BondHarmonic::extract(const char *str, int &dim)
 {
   dim = 1;
   if (strcmp(str,"kappa")==0) return (void*) k;

src/MOLECULE/bond_harmonic.h

@@ -35,7 +35,7 @@ class BondHarmonic : public Bond {
   virtual void read_restart(FILE *);
   void write_data(FILE *);
   double single(int, double, int, int, double &);
-  virtual void *extract(char *, int &);
+  virtual void *extract(const char *, int &);
 
  protected:
   double *k,*r0;

src/MOLECULE/bond_morse.cpp

@@ -209,7 +209,7 @@ double BondMorse::single(int type, double rsq, int /*i*/, int /*j*/,
 
 /* ---------------------------------------------------------------------- */
 
-void *BondMorse::extract(char *str, int &dim )
+void *BondMorse::extract(const char *str, int &dim)
 {
   dim = 1;
   if (strcmp(str,"r0")==0) return (void*) r0;

src/MOLECULE/bond_morse.h

@@ -35,7 +35,7 @@ class BondMorse : public Bond {
   void read_restart(FILE *);
   void write_data(FILE *);
   double single(int, double, int, int, double &);
-  virtual void *extract(char *, int &);
+  virtual void *extract(const char *, int &);
 
  protected:
   double *d0,*alpha,*r0;

src/MOLECULE/bond_nonlinear.cpp

@@ -206,7 +206,7 @@ double BondNonlinear::single(int type, double rsq, int /*i*/, int /*j*/,
 
 /* ---------------------------------------------------------------------- */
 
-void *BondNonlinear::extract( char *str, int &dim )
+void *BondNonlinear::extract(const char *str, int &dim)
 {
   dim = 1;
   if (strcmp(str,"epsilon")==0) return (void*) epsilon;

src/MOLECULE/bond_nonlinear.h

@@ -35,7 +35,7 @@ class BondNonlinear : public Bond {
   void read_restart(FILE *);
   void write_data(FILE *);
   double single(int, double, int, int, double &);
-  virtual void *extract(char *, int &);
+  virtual void *extract(const char *, int &);
 
  protected:
   double *epsilon,*r0,*lamda;

src/bond.h

@@ -52,7 +52,7 @@ class Bond : protected Pointers {
   virtual void write_data(FILE *) {}
   virtual double single(int, double, int, int, double &) = 0;
   virtual double memory_usage();
-  virtual void *extract(char *, int &) {return NULL;}
+  virtual void *extract(const char *, int &) {return NULL;}
   virtual void reinit();
 
   void write_file(int, char**);