diff --git a/lang/cpp/src/context.cpp b/lang/cpp/src/context.cpp
index 50726816..6d840f06 100644
--- a/lang/cpp/src/context.cpp
+++ b/lang/cpp/src/context.cpp
@@ -1154,6 +1154,7 @@ Error Context::startCombinedDecryptionAndVerification(const Data &cipherText, Da
     return startCombinedDecryptionAndVerification(cipherText, plainText, DecryptNone);
 }
 
+namespace {
 unsigned int to_auditlog_flags(unsigned int flags)
 {
     unsigned int result = 0;
@@ -1168,6 +1169,7 @@ unsigned int to_auditlog_flags(unsigned int flags)
     }
     return result;
 }
+}
 
 Error Context::startGetAuditLog(Data &output, unsigned int flags)
 {