diff --git a/library/oid.c b/library/oid.c
index 75b0ee0..7bb5631 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -36,6 +36,12 @@
 #include <stdio.h>
 #include <string.h>
 
+#if defined(POLARSSL_PLATFORM_C)
+#include "polarssl/platform.h"
+#else
+#define polarssl_snprintf snprintf
+#endif
+
 #if defined(POLARSSL_X509_USE_C) || defined(POLARSSL_X509_CREATE_C)
 #include "polarssl/x509.h"
 #endif
@@ -653,7 +659,7 @@
     /* First byte contains first two dots */
     if( oid->len > 0 )
     {
-        ret = snprintf( p, n, "%d.%d", oid->p[0] / 40, oid->p[0] % 40 );
+        ret = polarssl_snprintf( p, n, "%d.%d", oid->p[0] / 40, oid->p[0] % 40 );
         SAFE_SNPRINTF();
     }
 
@@ -670,7 +676,7 @@
         if( !( oid->p[i] & 0x80 ) )
         {
             /* Last byte */
-            ret = snprintf( p, n, ".%d", value );
+            ret = polarssl_snprintf( p, n, ".%d", value );
             SAFE_SNPRINTF();
             value = 0;
         }