------- Comment #6 from burnus at gcc dot gnu dot org 2010-02-23 09:08 ------- Regarding my question, Toon ask this question to Bill Long @ Cray and Jim Xia @ IBM at the Las Vegas meeting of J3/WG5 - they came to different conclusions ;-)
Bill Long stated what he also wrote at http://j3-fortran.org/pipermail/j3/2010-February/003358.html Namely: The "OR" is to be read as exclusive "OR": > > Does a common block containing a single variable (e.g. of type > > "integer(c_int)") need to be interoperable with the C variable ("int") > > only [i.e. only (2)] > > Yes, this is my interpretation. Toon agreed more with Bill and commented: "I think this is due to the fact that - as every 'vendor' knows - the C compiler being the 'companion processor' (C interoperability terminology) to its Fortran processor, it can allow additional interoperability (for instance, allow COMMON /blah/ I interoperate with struct {int i;} blah;)." Thus, from the standard in a three-to-two-reading*, one only needs to interoperate with the single variable and not with the struct. (* My reading, Toon's, Bill's vs. Nick's (fort...@gcc) and Jim's.) -- Note: I have not submitted an official interpretation request, for which all J3/WG5 members have to vote. I really wonder whether supporting both in LTO would be the better option compared with changing it to a single variable in the frontend. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41227
