On HP-UX 11.00..11.31, with cc but not with gcc, the copysignl test fails:
test-copysignl.c:96: assertion failed
FAIL: test-copysignl
The reason is that the compiler implements the unary minus operator
incorrectly (!). Here is a workaround, limited to copysignl(), since we
cannot fix the problem in full generality.
2011-11-06 Bruno Haible <br...@clisp.org>
copysignl: Fix result for zero argument on HP-UX 11 with HP C.
* lib/copysignl.c (compute_minus_zerol) [HP-UX]: New function.
(minus_zerol) [HP-UX]: New macro.
(unary_minus) [HP-UX]: New function.
(copysignl) [HP-UX]: Use unary_minus function.
--- lib/copysignl.c.orig Sun Nov 6 19:12:31 2011
+++ lib/copysignl.c Sun Nov 6 19:10:47 2011
@@ -29,10 +29,44 @@
#else
+# if defined __hpux && !defined __GNUC__
+
+# include <float.h>
+
+/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0L. */
+static long double
+compute_minus_zerol (void)
+{
+ return -LDBL_MIN * LDBL_MIN;
+}
+# define minus_zerol compute_minus_zerol ()
+
+/* HP cc on HP-UX 11 has a bug: When x is a positive zero, - x comes out
+ as a positive zero, rather than as a minus zero. Work around it. */
+static long double
+unary_minus (long double x)
+{
+ if (x == 0.0L)
+ {
+ if (signbit (x))
+ return 0.0L;
+ else
+ return minus_zerol;
+ }
+ else
+ return - x;
+}
+
+# endif
+
long double
copysignl (long double x, long double y)
{
+# if defined __hpux && !defined __GNUC__
+ return (signbit (x) != signbit (y) ? unary_minus (x) : x);
+# else
return (signbit (x) != signbit (y) ? - x : x);
+# endif
}
#endif
--
In memoriam Louis Philippe d'Orléans
<http://en.wikipedia.org/wiki/Louis_Philippe_II,_Duke_of_Orléans>
