infinity, NaN formatted differently on different platforms

$ cat u.cpp && uname -sr && make u -r && ./u
#include <iostream>
#include <limits>

int main ()
{
    std::cout << std::numeric_limits<double>::infinity () << '\n'
              << std::numeric_limits<double>::quiet_NaN () << '\n'
              << std::numeric_limits<double>::signaling_NaN () << '\n'; 
}
SunOS 5.9
gcc -c -I/build/sebor/dev/stdlib/include/ansi -D_RWSTDDEBUG   -pthreads -D_RWSTD_USE_CONFIG -I/build/sebor/gcc-3.4.3-15s/include -I/build/sebor/dev/stdlib/include -I/build/sebor/dev/stdlib/examples/include  -pedantic -nostdinc++ -g  -Wall -W -Wcast-qual -Winline -Wshadow -Wwrite-strings -Wno-long-long  u.cpp
gcc u.o -o u -pthreads -L/build/sebor/gcc-3.4.3-15s/lib -lstd15s  -lsupc++ -lm
rm u.o
inf
nan
nan

$ uname -vs && gmake u -r && ./u
AIX 5
xlCcore_r -c -I/build/sebor/dev/stdlib/include/ansi -D_RWSTDDEBUG    -D_RWSTD_USE_CONFIG -I/build/sebor/vacpp-7.0.0.3-15D/include -I/build/sebor/dev/stdlib/include -I/build/sebor/dev/stdlib/examples/include  -g  -q64  -qtemplateregistry=u.ti   u.cpp
xlCcore_r u.o -o u -I/build/sebor/dev/stdlib/include/ansi -D_RWSTDDEBUG    -D_RWSTD_USE_CONFIG -liconv -brtl   -q64 -I/build/sebor/dev/stdlib/include/ansi -D_RWSTDDEBUG    -D_RWSTD_USE_CONFIG -I/build/sebor/vacpp-7.0.0.3-15D/include -I/build/sebor/dev/stdlib/include -I/build/sebor/dev/stdlib/examples/include  -qtemplateregistry=u.ti -L/build/sebor/vacpp-7.0.0.3-15D/lib -lstd15D   -lm
rm u.o
inf
nanq
nans