diff --git a/include/polarssl/x509write.h b/include/polarssl/x509write.h
index 8ce3d8669..a0d7ff8f2 100644
--- a/include/polarssl/x509write.h
+++ b/include/polarssl/x509write.h
@@ -29,6 +29,10 @@
 
 #include "rsa.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct _x509_req_name
 {
     char oid[128];
@@ -43,4 +47,8 @@ int x509_write_key_der( unsigned char *buf, size_t size, rsa_context *rsa );
 int x509_write_cert_req( unsigned char *buf, size_t size, rsa_context *rsa,
                          x509_req_name *req_name, int hash_id );
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* POLARSSL_X509_WRITE_H */