--- trunk/OOPSE/libmdtools/Verlet.cpp	2003/04/14 21:16:37	497
+++ trunk/OOPSE/libmdtools/Verlet.cpp	2003/05/30 21:31:48	542
@@ -9,6 +9,8 @@ extern "C"{
 #include "ReadWrite.hpp"
 #include "ExtendedSystem.hpp"
 
+#include "simError.h"
+
 extern "C"{
   
   void v_constrain_a_( double &dt, int &n_atoms, double* mass, 
@@ -17,7 +19,8 @@ extern "C"{
 		       double* Fx, double* Fy, double* Fz, 
 		       int &n_constrained, double *constr_sqr,
 		       int* constr_i, int* constr_j, 
-		       double &box_x, double &box_y, double &box_z );
+		       double &box_x, double &box_y, double &box_z,
+		       int &isError );
 
   void v_constrain_b_( double &dt, int &n_atoms, double* mass, 
 		       double* Rx, double* Ry, double* Rz, 
@@ -26,7 +29,8 @@ extern "C"{
 		       double &Kinetic, 
 		       int &n_constrained, double *constr_sqr,
 		       int* constr_i, int* constr_j, 
-		       double &box_x, double &box_y, double &box_z );
+		       double &box_x, double &box_y, double &box_z,
+		       int &isError);
 }
 
   
@@ -198,6 +202,8 @@ void Verlet::integrate( void ){
   int status_n = (int)( statusTime / dt );
   int vel_n    = (int)( thermalTime / dt );
 
+  int isError;
+
   Thermo *tStats = new Thermo( entry_plug );
 
   StatWriter*  e_out    = new StatWriter( entry_plug );
@@ -245,12 +251,29 @@ void Verlet::integrate( void ){
 
       }
       
+      isError = 0;
       v_constrain_a_( dt, c_natoms, c_mass, Rx, Ry, Rz, Vx, Vy, Vz, 
 		      Fx, Fy, Fz,
 		      c_n_constrained, c_constrained_dsqr, 
 		      c_constrained_i, c_constrained_j,
-		      c_box_x, c_box_y, c_box_z );
+		      c_box_x, c_box_y, c_box_z,
+		      isError);
+
+      if( isError ){
+	
+	sprintf( painCave.errMsg,
+		 "Constraint Failure in Fortran move A\n" );
+	painCave.isFatal = 1;
+	simError();
+      }
+      
+#ifdef IS_MPI
+      sprintf( checkPointMsg,
+	       "succesful return from move a.\n" );
+      MPIcheckPoint();
 
+#endif //is_mpi
+
       for( j=0; j<c_natoms; j++ ){
 
 	c_atoms[j]->setX(Rx[j]);
@@ -287,12 +310,29 @@ void Verlet::integrate( void ){
       }
 	
 
+      isError = 0;
       v_constrain_b_( dt, c_natoms, c_mass, Rx, Ry, Rz, Vx, Vy, Vz, 
 		      Fx, Fy, Fz,
 		      kE, c_n_constrained, c_constrained_dsqr, 
 		      c_constrained_i, c_constrained_j,
-		      c_box_x, c_box_y, c_box_z );
-      
+		      c_box_x, c_box_y, c_box_z, isError );
+
+      if( isError ){
+	
+	sprintf( painCave.errMsg,
+		 "Constraint Failure in Fortran move B\n" );
+	painCave.isFatal = 1;
+	simError();
+      }
+
+#ifdef IS_MPI
+      sprintf( checkPointMsg,
+	       "succesful return from move B.\n" );
+      MPIcheckPoint();
+
+#endif //is_mpi      
+
+
       for( j=0; j<c_natoms; j++ ){
 
 	c_atoms[j]->setX(Rx[j]);