diff --git a/components/lazdebuggers/lazdebuggerintf/lazdebuggerintffloattypes.pas b/components/lazdebuggers/lazdebuggerintf/lazdebuggerintffloattypes.pas
index 255a285010..99bb3fa237 100644
--- a/components/lazdebuggers/lazdebuggerintf/lazdebuggerintffloattypes.pas
+++ b/components/lazdebuggers/lazdebuggerintf/lazdebuggerintffloattypes.pas
@@ -71,12 +71,12 @@ type
 
 implementation
 
-var
+threadvar
   EM: TFPUExceptionMask;
   {$ifdef HAS_SOFT_EXTENDED}
   SEM: TFPUExceptionMask;
   {$endif}
-  FloatExceptionLock: integer = 0;
+  FloatExceptionLock: integer;
 
 
 procedure DisableFloatExceptions;