SERVER-5738 Remove MONGO_ONCE in favor of std::call_once

1 files changed, 5 insertions, 2 deletions

diff --git a/src/mongo/db/auth/authz_session_external_state_server_common.cpp b/src/mongo/db/auth/authz_session_external_state_server_common.cpp
index e2416596c4b..faf039ba7dc 100644
--- a/src/mongo/db/auth/authz_session_external_state_server_common.cpp
+++ b/src/mongo/db/auth/authz_session_external_state_server_common.cpp
@@ -32,6 +32,8 @@
 
 #include "mongo/db/auth/authz_session_external_state_server_common.h"
 
+#include <mutex>
+
 #include "mongo/base/status.h"
 #include "mongo/db/auth/authorization_manager.h"
 #include "mongo/db/client.h"
@@ -43,6 +45,7 @@ namespace mongo {
 
 namespace {
 MONGO_EXPORT_STARTUP_SERVER_PARAMETER(enableLocalhostAuthBypass, bool, true);
+std::once_flag checkShouldAllowLocalhostOnceFlag;
 }  // namespace
 
 // NOTE: we default _allowLocalhost to true under the assumption that _checkShouldAllowLocalhost
@@ -67,11 +70,11 @@ void AuthzSessionExternalStateServerCommon::_checkShouldAllowLocalhost(Operation
 
     _allowLocalhost = !_authzManager->hasAnyPrivilegeDocuments(txn);
     if (_allowLocalhost) {
-        ONCE {
+        std::call_once(checkShouldAllowLocalhostOnceFlag, []() {
             log() << "note: no users configured in admin.system.users, allowing localhost "
                      "access"
                   << std::endl;
-        }
+        });
     }
 }