diff --git a/include/cmetrics/cmt_compat.h b/include/cmetrics/cmt_compat.h
index d7d2510..a4f8a9d 100644
--- a/include/cmetrics/cmt_compat.h
+++ b/include/cmetrics/cmt_compat.h
@@ -23,9 +23,30 @@
 #include <time.h>
 #ifdef _WIN32
 #include <windows.h>
-#define strtok_r strtok_s
 #endif
 
+/* This function is copied from monkey/monkey.
+   https://github.com/monkey/monkey/blob/2567a70912ed7a68d9e75dca3cf22d3927fea99a/mk_core/deps/libevent/evdns.c#L3323 */
+static inline char *
+cmt_platform_strtok_r(char *s, const char *delim, char **state) {
+    char *cp, *start;
+    start = cp = s ? s : *state;
+    if (!cp)
+        return NULL;
+    while (*cp && !strchr(delim, *cp))
+        ++cp;
+    if (!*cp) {
+        if (cp == start)
+            return NULL;
+        *state = NULL;
+        return start;
+    } else {
+        *cp++ = '\0';
+        *state = cp;
+        return start;
+    }
+}
+
 static inline struct tm *cmt_platform_gmtime_r(const time_t *timep, struct tm *result)
 {
 #ifdef CMT_HAVE_GMTIME_S
diff --git a/src/cmt_decode_statsd.c b/src/cmt_decode_statsd.c
index 130fa43..34f77b9 100644
--- a/src/cmt_decode_statsd.c
+++ b/src/cmt_decode_statsd.c
@@ -134,7 +134,7 @@ static int decode_labels(struct cmt *cmt,
     }
 
     if (labels != NULL) {
-        label_kv = strtok_r(labels, ",", &store);
+        label_kv = cmt_platform_strtok_r(labels, ",", &store);
 
         while (label_kv != NULL) {
             colon = strchr(label_kv, ':');
@@ -185,7 +185,7 @@ static int decode_labels(struct cmt *cmt,
             cfl_sds_destroy(label_k);
 
         retry:
-            label_kv = strtok_r(NULL, ",", &store);
+            label_kv = cmt_platform_strtok_r(NULL, ",", &store);
         }
     }
 
@@ -524,7 +524,7 @@ static int decode_metrics_lines(struct cmt *cmt,
     char *line = NULL;
     char *store = NULL;
 
-    line = strtok_r(in_buf, "\n", &store);
+    line = cmt_platform_strtok_r(in_buf, "\n", &store);
     while (line != NULL) {
         /* StatsD format always has | at least one. */
         if (strstr(line, "|") == NULL) {
@@ -538,7 +538,7 @@ static int decode_metrics_lines(struct cmt *cmt,
             break;
         }
 retry:
-        line = strtok_r(NULL, "\n", &store);
+        line = cmt_platform_strtok_r(NULL, "\n", &store);
     }
 
     return ret;