diff --git a/src/BER.h b/src/BER.h
index e542f7e..2fb9bb6 100644
--- a/src/BER.h
+++ b/src/BER.h
@@ -7,26 +7,32 @@
 #ifdef __has_include
 #if __has_include("SNMPcfg.h")
 #include "SNMPcfg.h"
-#else
+#endif
+#endif
+
 /**
  * @def SNMP_STREAM
  * @brief Defines read and write operations.
  */
+#ifndef SNMP_STREAM
 #define SNMP_STREAM 1
+#endif
 
 /**
  * @def SNMP_VECTOR
  * @brief Defines storage for ArrayBER.
  */
+#ifndef SNMP_VECTOR
 #define SNMP_VECTOR 0
+#endif
 
 /**
  * @def SNMP_CAPACITY
  * @brief Defines capacity of SequenceBER.
  */
+#ifndef SNMP_CAPACITY
 #define SNMP_CAPACITY 6
 #endif
-#endif
 
 #if SNMP_STREAM
 #include <Stream.h>