On Thu, Apr 14, 2005 at 11:30:20PM +0200, Jason Merrill wrote: > Consider Double-Checked Locking > (http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html). > I used DCL with explicit memory barriers to implement thread-safe > initialization of function-local statics > (libstdc++-v3/libsupc++/guard.cc). The proposed change to volatile > semantics would allow me to write it more simply, by just making the > initialized flag volatile. Yes, volatile would be stronger than is > actually necessary for DCLP, but I don't have to use it if I want > finer-grained control over the synchronization.
Is there any reason to want to overload volatile for this, rather than template<classname T> T acquire(T *ptr); template<classname T> void release(T *ptr, T val); where the functions do the indirection plus the memory ordering? The biggest problem that I see is that C and C++ have been around far too long, and there are far too many existing uses of "volatile" to be redefining it now. r~
