diff --git a/src/lib/math/isosurf/implicit.c b/src/lib/math/isosurf/implicit.c
index c02a0e1..bf37f5c 100644
--- a/src/lib/math/isosurf/implicit.c
+++ b/src/lib/math/isosurf/implicit.c
@@ -124,8 +124,8 @@ typedef struct intlists {	   /* list of list of integers */
 } INTLISTS;
 
 typedef struct process {	   /* parameters, function, storage */
-    double (*function)();	   /* implicit surface function */
-    int (*triproc)();		   /* triangle output function */
+    double (*function)(double, double, double);	   /* implicit surface function */
+    int (*triproc)(int, int, int, VERTICES);		   /* triangle output function */
     double size, delta;		   /* cube size, normal delta */
     int bounds;			   /* cube range within lattice */
     POINT start;		   /* start point on surface */
@@ -136,14 +136,12 @@ typedef struct process {	   /* parameters, function, storage */
     EDGELIST **edges;		   /* edge and vertex id hash table */
 } PROCESS;
 
-void *calloc();
-
 #define mycalloc(n,nbyte) _mycalloc(n,nbyte,__LINE__)
 #define myfree(ptr) _myfree(ptr,__LINE__)
 
 static void makecubetable ();
 static void free_cubetable();
-static void converge(POINT*,POINT*,double,double(*f)(),POINT*);
+static void converge(POINT*,POINT*,double,double(*f)(double, double, double),POINT*);
 static CORNER *setcorner (PROCESS*, int, int, int);
 static int setcenter(CENTERLIST *table[], int, int, int);
 static int dotet (CUBE*, int, int, int, int, PROCESS*);
@@ -231,7 +229,7 @@ VERTICES vertices;
 
 main ()
 {
-    char *err, *polygonize();
+    char *err;
 
     keepaspect(1, 1);
     winopen("implicit");
@@ -346,13 +344,12 @@ main ()
  */
 
 char *polygonize (function, size, bounds, x, y, z, triproc, mode)
-double (*function)(), size, x, y, z;
-int bounds, (*triproc)(), mode;
+double (*function)(double, double, double), size, x, y, z;
+int bounds, (*triproc)(int, int, int, VERTICES), mode;
 {
     PROCESS p;
     int n, noabort;
-    CORNER *setcorner();
-    TEST in, out, find();
+    TEST in, out;
 
     p.function = function;
     p.triproc = triproc;
@@ -499,7 +496,6 @@ int i, j, k, face, c1, c2, c3, c4;
 {
     CUBE new;
     CUBES *oldcubes = p->cubes;
-    CORNER *setcorner();
     int n, pos = old->corners[c1]->value > 0.0 ? 1 : 0;
     /* static int facebit[6] = {2, 2, 1, 1, 0, 0}; */
     /* int bit = facebit[face]; */
@@ -1015,7 +1011,7 @@ PROCESS *p;
 
 static void converge (p1, p2, v, function, p)
 double v;
-double (*function)();
+double (*function)(double, double, double);
 POINT *p1, *p2, *p;
 {
     int i = 0;