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-rw-r--r--generic/tcl.h12
1 files changed, 7 insertions, 5 deletions
diff --git a/generic/tcl.h b/generic/tcl.h
index 147672c..5a85c33 100644
--- a/generic/tcl.h
+++ b/generic/tcl.h
@@ -854,10 +854,7 @@ typedef struct Tcl_Obj {
* whether an object is shared (i.e. has reference count > 1). Note: clients
* should use Tcl_DecrRefCount() when they are finished using an object, and
* should never call TclFreeObj() directly. TclFreeObj() is only defined and
- * made public in tcl.h to support Tcl_DecrRefCount's macro definition. Note
- * also that Tcl_DecrRefCount() refers to the parameter "obj" twice. This
- * means that you should avoid calling it with an expression that is expensive
- * to compute or has side effects.
+ * made public in tcl.h to support Tcl_DecrRefCount's macro definition.
*/
void Tcl_IncrRefCount(Tcl_Obj *objPtr);
@@ -2504,7 +2501,12 @@ EXTERN void Tcl_GetMemoryInfo(Tcl_DString *dsPtr);
* http://c2.com/cgi/wiki?TrivialDoWhileLoop
*/
# define Tcl_DecrRefCount(objPtr) \
- do { if (--(objPtr)->refCount <= 0) TclFreeObj(objPtr); } while(0)
+ do { \
+ Tcl_Obj *obj = (objPtr); \
+ if ((obj)->refCount-- < 2) { \
+ TclFreeObj(obj); \
+ } \
+ } while(0)
# define Tcl_IsShared(objPtr) \
((objPtr)->refCount > 1)
#endif