Marco Atzeri wrote:
> Dear all,
> unfortunately I am not too much familiar with C++,
> so I have no clue where to look for difference
> between Cygwin and all the other platforms where this
> problem does not happen.
I'm not that hot on C++ templates either, but it's probably something to do
with different native types affecting name resolution at a guess.
> Only on cygwin, both with gcc-3 and gcc-4,
> the building from last development
> sources of octave-3.1.51+ stop here:
> Any suggestion ?
#1: Use STLfilt!
BD Software STL Message Decryptor v3.10 for gcc 2/3/4
../../octave_local/liboctave/oct-inttypes.cc:516: error: ambiguous template
specialization `mop<octave_int_cmp_op::ne>' for
`bool octave _int_cmp_op::mop(uint64_t, double)'
../../octave_local/liboctave/oct-inttypes.h: In function
`bool operator<(const double &, const octave_int<uint64_t> &)':
../../octave_local/liboctave/oct-inttypes.h:1054:error: call of overloaded
`mop(const double &, uint64_t)' is ambiguous
../../octave_local/liboctave/oct-inttypes.h:193: candidates are: static bool
octave_int_cmp_op::mop(
T,
double)
../../octave_local/liboctave/oct-inttypes.h:198: static bool octave_int_cmp_op
::mop(double, long long unsigned int)
../../octave_local/liboctave/oct-inttypes.cc:60: static bool octave_int_cmp_op
::mop(uint64_t, double)
../../octave_local/liboctave/oct-inttypes.cc:80: static bool octave_int_cmp_op
::mop(int64_t, double)
../../octave_local/liboctave/oct-inttypes.cc:127: static bool
octave_int_cmp_op::mop(double, uint64_t)
../../octave_local/liboctave/oct-inttypes.cc:135: static bool
octave_int_cmp_op::mop(double, int64_t)
Hmm. The generic template with the <T> is less specific and shouldn't
matter if there's a more-specific one, which there is. So, why doesn't the
(uint64_t, double) version match? Well, looking at the other possible
matches, it seems to think that int64_t is as near a match. I wonder if when
it doesn't have an exact match, it sees sign-extension and size-promotion as
equally different and therefore equally similar and therefore ambiguous. You
could find a C++ expert to explain the resolution rules for you, but I think
that's the sort of basis on which it works.
I wonder what would happen if, on Cygwin, uint64_t was a typedef for
unsigned long long int. Does it help if you comment out the <double, long
long unsigned int> template on line 198, leaving just the <double, uint64_t>
on line 127 to be a precise match?
cheers,
DaveK
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