On 31/01/19 22:29 +0100, François Dumont wrote:
I was writing a test which needed to override the std::nothrow
versions of the operator new and delete to control
get_temporary_buffer behavior and noticed that it is inconsistent
with release_temporary_buffer in terms of new/delete operators.
Grepping for other std::nothrow usages I found some others and
especially one in libsupc++.
I don't know how serious it is considering the Standard. As long
as you stick to the libstdc++ operators it is fine. Only users
overriding those operators will notice.
Tested under Linux x86_64 normal mode with some failures but none
related to this patch I think but of course you better check on your
side.
* libsupc++/atexit_thread.cc (run(void*)): Call std::nothrow delete
operator.
* include/bits/stl_tempbuf.h (return_temporary_buffer): Likewise.
* include/profile/impl/profiler_trace.h
(__trace_base<>::~__trace_base()): Likewise.
(__trace_base<>::__add_object(__stack_t)): Likewise.
(__trace_base<>::__retire_object(__stack_t)): Likewise.
Let me know if it is a go.
Nope.
François
diff --git a/libstdc++-v3/include/bits/stl_tempbuf.h
b/libstdc++-v3/include/bits/stl_tempbuf.h
index b6ad9ee6a46..e614a77bc4f 100644
--- a/libstdc++-v3/include/bits/stl_tempbuf.h
+++ b/libstdc++-v3/include/bits/stl_tempbuf.h
@@ -110,7 +110,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Tp>
inline void
return_temporary_buffer(_Tp* __p)
- { ::operator delete(__p); }
+ { ::operator delete(__p, std::nothrow); }
This change is harmless, but unnecessary.
The standard requires that the nothrow versions of operator new must
obtain memory from the same source as the normal version of operator
new (even if the user has replaced one or both versions of operator
new). That means you can always use the normal version of operator
delete instead of the nothrow one.
If your tests failed because of this, then your replacement versions
of operator new and operator delete were wrong.
See [new.delete.single] p7.