[HP-UX/IPF] NaN has the wrong sign

• Key: STDCXX-797
• Type: Bug
• Status: Open
• Priority: Minor
• Assignee: Unassigned
• Reporter: Martin Sebor
• Component/s: 18. Language Support
• Affects Version/s: 4.2.0
• Fix Version/s: 4.2.2

Environment

HP-UX B.11.31
aCC: HP C/aC++ B3910B A.06.16 [Nov 26 2007]

Description

On HP-UX/IPF, std::numeric_limits<T>::quiet_NaN() has the wrong sign for all floating point types T:

$ cat t.cpp && uname -sr && aCC -V && aCC -AA t.cpp && ./a.out && gmake t && ./t
#include <cassert>
#include <cmath>
#include <limits>

template <class T>
void test (T x, T expect)
{
    assert (fpclassify (x) == fpclassify (expect));
    assert (signbit (x) == signbit (expect));
}

int main ()
{
    test (std::numeric_limits<float>::quiet_NaN (), float (NAN));
    test (-std::numeric_limits<float>::quiet_NaN (), -float (NAN));

    test (std::numeric_limits<double>::quiet_NaN (), double (NAN));
    test (-std::numeric_limits<double>::quiet_NaN (), -double (NAN));

    test (std::numeric_limits<long double>::quiet_NaN (), (long double)NAN);
    test (-std::numeric_limits<long double>::quiet_NaN (), -(long double)NAN);
}
HP-UX B.11.31
aCC: HP C/aC++ B3910B A.06.16 [Nov 26 2007]
aCC -c  -D_RWSTDDEBUG   -mt -I/amd/devco/sebor/stdcxx/include -I/build/sebor/stdcxx-aCC-6.16-15D/include \
    -I/amd/devco/sebor/stdcxx/examples/include  -AA  -g +d  +DD64 +w \
    +W392 +W655 +W684 +W818 +W819 +W849 +W2193 +W2236 +W2261 +W2340 +W2401 +W2487 +W4227 +W4229 \
    +W4231 +W4235 +W4237 +W4249 +W4255 +W4272 +W4284 +W4285 +W4286 +W4296 +W4297 +W3348   t.cpp
"/amd/devco/sebor/stdcxx/include/limits", line 449: warning #4070-D: floating
          point underflow exception
      _RWSTD_STATIC_FUN (long double, (min), _RWSTD_LDBL_MIN) 
      ^

aCC t.o -o t -AA +nostl -Wl,+s   -mt +DD64 -L/build/sebor/stdcxx-aCC-6.16-15D/lib  -Wl,+b/build/sebor/stdcxx-aCC-6.16-15D/lib -lstd15D  -lm 
Assertion failed: signbit (x) == signbit (expect), file t.cpp, line 9
ABORT instruction (core dumped)