diff --git a/prism/include/hybrid.h b/prism/include/hybrid.h
index 1ad18fba..6390ab74 100644
--- a/prism/include/hybrid.h
+++ b/prism/include/hybrid.h
@@ -32,7 +32,7 @@
 
 //------------------------------------------------------------------------------
 
-int fatal(char *s); 
+void fatal(char *s); 
 
 // hdd data structure definitions
 
diff --git a/prism/src/dd/dd_info.cc b/prism/src/dd/dd_info.cc
index 3dc4e3c3..2261ce39 100644
--- a/prism/src/dd/dd_info.cc
+++ b/prism/src/dd/dd_info.cc
@@ -195,7 +195,7 @@ bool and_numbers)
 	Cudd_RecursiveDeref(ddman, tmp);
 	// Finally, print if there are (and possibly how many) minus infinities
 	if (and_numbers) {
-		if (count < (1<<num_vars)) fprintf(dd_out, "-inf (%.0f)", pow(2, num_vars) - count);
+		if (count < (1<<num_vars)) fprintf(dd_out, "-inf (%.0f)", pow(2.0, num_vars) - count);
 	} else {
 		if (min == -HUGE_VAL) fprintf(dd_out, "-inf");
 	}
diff --git a/prism/src/dd/dd_matrix.cc b/prism/src/dd/dd_matrix.cc
index 86c83e6c..94418302 100644
--- a/prism/src/dd/dd_matrix.cc
+++ b/prism/src/dd/dd_matrix.cc
@@ -379,7 +379,7 @@ int accuracy
 		inputs[j] = 0;
 	}
 		
-	length = (long)pow(2, num_vars);
+	length = (long)pow(2.0, num_vars);
 
 	for (i = 0; i < length; i++) {
 		for (j = 0; j < num_vars; j++) {			
@@ -443,8 +443,8 @@ int accuracy
 		inputs[k] = 0;
 	}
 		
-	rows = (long)pow(2, num_rvars);
-	cols = (long)pow(2, num_cvars);
+	rows = (long)pow(2.0, num_rvars);
+	cols = (long)pow(2.0, num_cvars);
 	
 	for (i = 0; i < rows; i++) {
 		for (j = 0; j < cols; j++) {
@@ -511,7 +511,7 @@ int accuracy
 		inputs[j] = 0;
 	}
 		
-	length = (long)pow(2, num_vars);
+	length = (long)pow(2.0, num_vars);
 
 	count = -1;
 	for (i = 0; i < length; i++) {
diff --git a/prism/src/dv/dv.cc b/prism/src/dv/dv.cc
index 5df01365..5649b76d 100644
--- a/prism/src/dv/dv.cc
+++ b/prism/src/dv/dv.cc
@@ -33,7 +33,7 @@
 static void mtbdd_to_double_vector_rec(DdManager *ddman, DdNode *dd, DdNode **vars, int num_vars, int level, ODDNode *odd, long o, double *res);
 static DdNode *double_vector_to_mtbdd_rec(DdManager *ddman, double *vec, DdNode **vars, int num_vars, int level, ODDNode *odd, long o);
 static DdNode *double_vector_to_bdd_rec(DdManager *ddman, double *vec, int rel_op, double bound1, double bound2, DdNode **vars, int num_vars, int level, ODDNode *odd, long o);
-static double filter_double_vector_rec(DdManager *ddman, double *vec, DdNode *filter, DdNode **vars, int num_vars, int level, ODDNode *odd, long o);
+static void filter_double_vector_rec(DdManager *ddman, double *vec, DdNode *filter, DdNode **vars, int num_vars, int level, ODDNode *odd, long o);
 static double get_first_from_bdd_rec(DdManager *ddman, double *vec, DdNode *filter, DdNode **vars, int num_vars, int level, ODDNode *odd, long o);
 static double min_double_vector_over_bdd_rec(DdManager *ddman, double *vec, DdNode *filter, DdNode **vars, int num_vars, int level, ODDNode *odd, long o);
 static double max_double_vector_over_bdd_rec(DdManager *ddman, double *vec, DdNode *filter, DdNode **vars, int num_vars, int level, ODDNode *odd, long o);
@@ -193,7 +193,7 @@ EXPORT void filter_double_vector(DdManager *ddman, double *vec, DdNode *filter,
 	filter_double_vector_rec(ddman, vec, filter, vars, num_vars, 0, odd, 0);
 }
 
-double filter_double_vector_rec(DdManager *ddman, double *vec, DdNode *filter, DdNode **vars, int num_vars, int level, ODDNode *odd, long o)
+void filter_double_vector_rec(DdManager *ddman, double *vec, DdNode *filter, DdNode **vars, int num_vars, int level, ODDNode *odd, long o)
 {
 	DdNode *dd;
 	
diff --git a/prism/src/hybrid/hybrid.cc b/prism/src/hybrid/hybrid.cc
index 9296d2e0..b4cef3c3 100644
--- a/prism/src/hybrid/hybrid.cc
+++ b/prism/src/hybrid/hybrid.cc
@@ -32,7 +32,7 @@
 #include "PrismHybridGlob.h"
 #include <math.h>
 
-int fatal( char *s) { fprintf(stderr, "fatal...\n"); perror(s); exit(10); }
+void fatal( char *s) { fprintf(stderr, "fatal...\n"); perror(s); exit(10); }
 
 // globals (used by local functions)
 static HDDMatrix *hddm;