diff --git a/cig/libcig.h b/cig/libcig.h
index 4e9913b..e310f1c 100644
--- a/cig/libcig.h
+++ b/cig/libcig.h
@@ -20,4 +20,4 @@ extern char *copystring(char *, const char *);
 
 extern scheme_value strlen_or_false(const char *);
 
-extern void cig_check_nargs(int arity, int nargs, char *fn);
+extern void cig_check_nargs(int arity, int nargs, const char *fn);
diff --git a/cig/libcig1.c b/cig/libcig1.c
index 52b52f4..e58989f 100644
--- a/cig/libcig1.c
+++ b/cig/libcig1.c
@@ -17,7 +17,7 @@
 ** If C string is NULL, do nothing and return #f.
 */
 
-int c2scheme_strcpy(scheme_value sstr, char *cstr)
+int c2scheme_strcpy(scheme_value sstr, const char *cstr)
 {
     if( cstr ) {
 	strncpy( (char*) StobData(sstr), cstr, STRING_LENGTH(sstr) );
@@ -28,7 +28,7 @@ int c2scheme_strcpy(scheme_value sstr, char *cstr)
 
 
 /* Same as above, but free the C string when we are done. */
-int c2scheme_strcpy_free(scheme_value sstr, char *cstr)
+int c2scheme_strcpy_free(scheme_value sstr, const char *cstr)
 {
     if( cstr ) {
 	strncpy( (char*) StobData(sstr), cstr, STRING_LENGTH(sstr) );
@@ -42,11 +42,10 @@ char *scheme2c_strcpy(scheme_value sstr)
 {
     char *result;
     int slen;
-    extern void *memcpy(void*, const void*, size_t);
     extern int errno;
 
     slen = STRING_LENGTH(sstr);
-    result = (char*) malloc(slen+1);
+    result = Malloc(char, slen+1);
 
     if( result == NULL ) {
         fprintf(stderr,
@@ -56,7 +55,7 @@ char *scheme2c_strcpy(scheme_value sstr)
 	exit(-1);
 	}
 
-    memcpy(result, (void *) cig_string_body(sstr), slen);
+    memcpy(result, cig_string_body(sstr), slen);
     result[slen] = '\000';
     return result;
     }
@@ -66,9 +65,9 @@ char *scheme2c_strcpy(scheme_value sstr)
 **  The terminating null is not counted. Returns #f on NULL.
 */
 
-scheme_value c_veclen(long *vec)
+scheme_value c_veclen(const long *vec)
 {
-    long *vptr = vec;
+    const long *vptr = vec;
     if( !vptr ) return SCHFALSE;
     while( *vptr ) vptr++;
     return ENTER_FIXNUM(vptr - vec);
@@ -112,7 +111,7 @@ char *copystring_or_die(const char *str ) /* Note: NULL -> NULL. */
     else return NULL;
     }
 
-int cstring_nullp( char *s ) { return ! s; }
+int cstring_nullp( const char *s ) { return ! s; }
 
 scheme_value strlen_or_false(const char *s)
 { return s ?  ENTER_FIXNUM(strlen(s)) : SCHFALSE; }
@@ -138,7 +137,7 @@ void set_strvec_carriers(scheme_value svec, char const * const * cvec)
     }
 
 /* Helper function for arg checking. Why bother, actually? */
-void cig_check_nargs(int arity, int nargs, char *fn)
+void cig_check_nargs(int arity, int nargs, const char *fn)
 {
    if( arity != nargs ) {
        fprintf(stderr,