On Wed, Jan 9, 2013 at 12:34 AM, Tobias Burnus <bur...@net-b.de> wrote: > Janne Blomqvist worte: >> >> On Sun, Jan 6, 2013 at 6:52 PM, Tobias Burnus<bur...@net-b.de> wrote: >>> >>> >Attached is a small variation, which in addition handles the case that a >>> >>> >non-BOOL_C LOGICAL, Bind(C) dummy argument (or result variable) is used >>> > in a >>> >procedure call. In that case, the variable is now converted to a >>> >TYPE_PRECISION == 1 variable. -- The updated patch was build and >>> > regtested >>> >successfully. >> >> Nice, this should fix a pitfall with the previous patch. I still worry >> about these almost-but-not-quite logicals causing weird and very hard >> to track down bugs. > > > Though, it should be much less severe then with the current trunk. > >> A slightly safer variant of the approach youdescribe above would be to >> convert the variable directly after the bind(c) procedure call; that should >> make it pretty fool-proof, AFAICS? >> >> (in some cases that would be a bit of extra useless work, but I doubt >> it would matter performance-wise). > > > Well, that's not at trivial as it sounds. In particular for a > Fortran-written procedure, which gets the input from C. If the variable is > INTENT(IN) or if it is not modified in the procedure, it may not be touched. > In order to do this, one has to implement support for a shadow variable, > which has to set the real one at the end of the procedure. I don't think > that this shadow-var handling is really that trivial. > > For actual arguments, doing the conversion back is simpler. Function results > might be also a bit tricky, but that's mostly handled by the current patch, > I hope.
Ah, thanks for the clarification. I think if we cannot make it really bullet-proof, then it's safer to reject it outright. Do you happen to know if anyone except openmpi would be affected? If only openmpi, then we could give them a nudge and the issue would likely be fixed by the time gcc 4.8 rolls out to end users. -- Janne Blomqvist
