NEW ISSUE: CPP20012 and C20014 are misleading.

[Bryan Aupperle <aupperle@us.ibm.com>]

Target: CPPCNI CD04 Rev4 and CCNI CD04
Rev4

Description: CPP20012 and C20014 both
state: An SCA runtime MUST ensure that
a stateless scoped implementation instance object is only ever dispatched
on one thread at any one time. In addition, within the SCA lifecycle of
an instance, an SCA runtime MUST only make a single invocation of one business
function.

If an implementation truly is stateless
- i.e. does not use static variables and only uses data members (C++) global
variables (C, a stateless C++ implementation should never access a global
variable for holding property values - than this statement is unnecessary.

The question becomes what kind of protection
can a runtime provide for in implementation identified as stateless that
is not truly so.  Static and global variables exist as long as the
library containing them  resides in memory and it is not possible
to guarantee that a library can be unloaded after an arbitrary function
invocation.  The second sentence of the normative statements implies
a level of protection that is simply not possible to provide. And newing/freeing
an object after every member function invocation is a performance hit.

The first sentence does not have any
problematic implications, but I think is meaningless in C.to the extent
that a function invocation only exists on one thread.

Proposal: At a minimum, the second sentence
of CPP20012 and C20014 should be deleted.  We should discuss if any
other changes are appropriate.

Bryan Aupperle, Ph.D.
STSM, WebSphere Enterprise Platform Software Solution Architect

Research Triangle Park,  NC 
+1 919-254-7508 (T/L 444-7508)
Internet Address: aupperle@us.ibm.com