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-rw-r--r--generic/tcl.h11
1 files changed, 7 insertions, 4 deletions
diff --git a/generic/tcl.h b/generic/tcl.h
index 36077e6..48fe062 100644
--- a/generic/tcl.h
+++ b/generic/tcl.h
@@ -810,9 +810,7 @@ typedef struct Tcl_Obj {
* 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.
+ * definition.
*/
void Tcl_IncrRefCount _ANSI_ARGS_((Tcl_Obj *objPtr));
void Tcl_DecrRefCount _ANSI_ARGS_((Tcl_Obj *objPtr));
@@ -833,7 +831,12 @@ int Tcl_IsShared _ANSI_ARGS_((Tcl_Obj *objPtr));
* 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