On Sat, Nov 2, 2013 at 5:10 PM, Jonathan Wakely <jwakely.gcc@xxxxxxxxx> wrote: > On 2 November 2013 21:03, Cyd Haselton <chaselton@xxxxxxxxx> wrote: >> On Sat, Nov 2, 2013 at 8:28 AM, Jonathan Wakely <jwakely.gcc@xxxxxxxxx> wrote: >>> On 27 October 2013 23:36, Cyd Haselton wrote: >>>> Android apparently doesn't support implicit conversion so had to do a >>>> cast before the argument is passed. >>> >>> N.B. it's not "Android" that doesn't support conversion from long >>> long* to long*, it's C++. >> >> Not sure what N.B. means... > > Did you try asking the web? > http://en.wikipedia.org/wiki/Nota_bene Honestly? I thought that there were so many things that N.B. could stand for that I didn't bother. Or I was so tired I didn't care. Take your pick. > > >> This is probably an obvious question but since I'm still working my >> way through C I have to ask: If C++ does not support that conversion, >> why is it in the code? And does C++ not support implicit conversion >> from long long* to long* or explicit, or both? > > The code passes the address of the field st_size to a function taking off_t*. > > The relevant standard says st_size should be type off_t, so there is > no conversion needed, and the code is correct. Ah. I think I see. C++ doesn't support implicit conversion but, in this case, implicit conversion should not be happening; st_size should be type off_t unless you're porting to Android in which case it's only off_t if you're targeting a mips platform. And thanks for this suggestion: > You could try: > > off_t ot = file->st.st_size; > Then pass &ot into the function and then: > file->st.st_size; = ot; After several tweaks in other areas the build finished and the cc1 binary runs correctly on device. Looking back I'd added this: off_t ot = file->st.st_size funct(args, &ot) then, when that didn't work I tried several variations of this: off_t *ot <---also off_t ot *snip* off_t ot = file->st.st_size <---also &file->st.st_size funct(args, &ot) <---also ot but I never added that last 'file->st.st_size = ot' because I didn't know it was necessary after the cast. I'm still not entirely sure why that line made the difference...I have a vague theory...but I'm certain I'll find out as I keep reading whichever C book I purchased from O'Reilly. Will update bug report tomorrow...and see if anyone's submitted a report to wherever they're tracking Android NDK stuff.
