https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68737
--- Comment #18 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I don't think we care about glibc < 2.0.6 though.
__max_digits * 4 is not enough for:
std::cout << std::fixed << std::numeric_limits<long double>::max();
That needs 4940 bytes, but we don't want to unconditionally alloca that amount.
Maybe:
--- a/libstdc++-v3/include/bits/locale_facets.tcc
+++ b/libstdc++-v3/include/bits/locale_facets.tcc
@@ -1008,6 +1008,11 @@ _GLIBCXX_BEGIN_NAMESPACE_LDBL
__len = std::__convert_from_v(_S_get_c_locale(), __cs, __cs_size,
__fbuf, __v);
+#ifdef __hpux
+ if (__len == -1)
+ __len = __cs_size = 5000;
+#endif
+
// If the buffer was not large enough, try again with the correct size.
if (__len >= __cs_size)
{
@@ -1020,6 +1025,11 @@ _GLIBCXX_BEGIN_NAMESPACE_LDBL
__len = std::__convert_from_v(_S_get_c_locale(), __cs, __cs_size,
__fbuf, __v);
}
+
+#ifdef __hpux
+ if (__len == -1)
+ return __s;
+#endif
#else
// Consider the possibility of long ios_base::fixed outputs
const bool __fixed = __io.flags() & ios_base::fixed;
