Mercurial > hg > octave-shane > gnulib-hg
annotate lib/signbitl.c @ 17282:a4996fb12971
locale: port to Solaris 2.6 and 7 + GNU gettext
* lib/locale.in.h: Just include_next <locale.h> when
being invoked recursively. This prevents problems on Solaris 2.6 and 7
when combining the localename module with GNU gettext 0.18.2.
Problem reported by Tom G. Christensen in
<http://lists.gnu.org/archive/html/bug-gnulib/2013-01/msg00084.html>.
| author | Paul Eggert <eggert@cs.ucla.edu> |
|---|---|
| date | Thu, 10 Jan 2013 13:24:13 -0800 |
| parents | e542fd46ad6f |
| children | 344018b6e5d7 |
| rev | line source |
|---|---|
| 8652 | 1 /* signbit() macro: Determine the sign bit of a floating-point number. |
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maint: update all copyright year number ranges
Eric Blake <eblake@redhat.com>
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2 Copyright (C) 2007, 2009-2013 Free Software Foundation, Inc. |
| 8652 | 3 |
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Change copyright notice from GPLv2+ to GPLv3+.
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4 This program is free software: you can redistribute it and/or modify |
| 8652 | 5 it under the terms of the GNU General Public License as published by |
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Bruno Haible <bruno@clisp.org>
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6 the Free Software Foundation; either version 3 of the License, or |
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7 (at your option) any later version. |
| 8652 | 8 |
| 9 This program is distributed in the hope that it will be useful, | |
| 10 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 12 GNU General Public License for more details. | |
| 13 | |
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14 You should have received a copy of the GNU General Public License |
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changeset
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15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 8652 | 16 |
| 17 #include <config.h> | |
| 18 | |
| 19 /* Specification. */ | |
| 20 #include <math.h> | |
| 21 | |
| 22 #include <string.h> | |
| 23 #include "isnanl-nolibm.h" | |
| 24 #include "float+.h" | |
| 25 | |
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26 #ifdef gl_signbitl_OPTIMIZED_MACRO |
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27 # undef gl_signbitl |
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28 #endif |
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29 |
| 8652 | 30 int |
| 31 gl_signbitl (long double arg) | |
| 32 { | |
| 33 #if defined LDBL_SIGNBIT_WORD && defined LDBL_SIGNBIT_BIT | |
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Bruno Haible <bruno@clisp.org>
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34 /* The use of a union to extract the bits of the representation of a |
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Bruno Haible <bruno@clisp.org>
parents:
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35 'long double' is safe in practice, despite of the "aliasing rules" of |
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Bruno Haible <bruno@clisp.org>
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36 C99, because the GCC docs say |
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37 "Even with '-fstrict-aliasing', type-punning is allowed, provided the |
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parents:
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38 memory is accessed through the union type." |
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39 and similarly for other compilers. */ |
| 8652 | 40 # define NWORDS \ |
| 41 ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int)) | |
| 42 union { long double value; unsigned int word[NWORDS]; } m; | |
| 43 m.value = arg; | |
| 44 return (m.word[LDBL_SIGNBIT_WORD] >> LDBL_SIGNBIT_BIT) & 1; | |
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45 #elif HAVE_COPYSIGNL_IN_LIBC |
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46 return copysignl (1.0L, arg) < 0; |
| 8652 | 47 #else |
| 48 /* This does not do the right thing for NaN, but this is irrelevant for | |
| 49 most use cases. */ | |
| 50 if (isnanl (arg)) | |
| 51 return 0; | |
| 52 if (arg < 0.0L) | |
| 53 return 1; | |
| 54 else if (arg == 0.0L) | |
| 55 { | |
| 56 /* Distinguish 0.0L and -0.0L. */ | |
| 57 static long double plus_zero = 0.0L; | |
| 58 long double arg_mem = arg; | |
| 59 return (memcmp (&plus_zero, &arg_mem, SIZEOF_LDBL) != 0); | |
| 60 } | |
| 61 else | |
| 62 return 0; | |
| 63 #endif | |
| 64 } |