--- src/cmdm_functions.c.orig	2018-02-26 06:43:36.000000000 +0800
+++ src/cmdm_functions.c	2025-06-28 23:42:07.000000000 +0800
@@ -308,10 +308,10 @@
 double **alloc_matrix(int n, int d) {
   int i;
   double **M;
-  M = Calloc(n, double *);
+  M = R_Calloc(n, double *);
 
   for (i = 0; i < n; i++) {
-    M[i] = Calloc(d, double);
+    M[i] = R_Calloc(d, double);
   }
   
   return M;
@@ -322,10 +322,10 @@
   int i;
 
   for (i = 0; i < n; i++) {
-    Free(M[i]);
+    R_Free(M[i]);
   }
 
-  Free(M);
+  R_Free(M);
 }
 
 // compute an n x n Euclidean distance matrix of an n x d matrix
@@ -352,7 +352,7 @@
 void reshape_demean(double *X, double **M, int n, int d) {
   int i, j;
   double *sum;
-  sum = Calloc(d, double);
+  sum = R_Calloc(d, double);
 
   for (i = 0; i < n; i++) {
     for (j = 0; j < d; j++) {
@@ -367,5 +367,5 @@
     }
   }
 
-  Free(sum);
+  R_Free(sum);
 }