11-163r1
To: J3
From: Nick Maclaren
Subject: Interop TR: the version member and CFI_establish
Date: 2011 June 29
Reference: N1854, 11-163, 11-168r1


There is a lack of clarity about when the version member is set.

During discussion, we agreed that the version member should be set on
establishment (i.e. always by CFI_establish, and never by other calls),
and that the implementation be given the option to determine what the
value of CFI_VERSION in the header used to compile the call to
CFI_establish, in case that it differs from that used when the code of
CFI_establish were compiled.


Edits to N1854:

[9:10] Before "functions" add "macro and".

[10:7] Append "when the descriptor is established and otherwise not
changed."

[13:3] Before "functions", add "macro and".

[16:18+] Add a new paragraph:

"It is unspecified whether CFI_establish is a macro or an identifier
declared with external linkage.  If a macro definition is suppressed in
order to access an actual function, the behavior is undefined."

[16:21+] Add a new note:

"NOTE 5.x

This function is allowed to be a macro to provide extra implementation
flexibility.  For example, it could include the value of CFI_VERSION in
the header used to compile the call to CFI_establish as an extra
argument of the actual function used to establish the descriptor."