Mercurial > gnulib
changeset 17644:bfa6d7414863
expl: avoid incorrect expl(small_value) on OpenBSD 5.4
OpenBSD 5.4, expl() incorrectly returns 'nan' for small values.
Detect this and use gnulib's expl() in that case.
Discussed here:
http://marc.info/?t=139159081700002&r=1&w=2
(Message from David Coppa on 2014-02-05 to openbsd-tech mailing list).
Fixed here (in revision 1.2):
http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libm/src/ld128/s_floorl.c
* m4/expl.m4 (gl_FUNC_EXPL): Add a check for this condition.
* doc/posix-functions/expl.texi: Mention the workaround.
| author | Assaf Gordon <agordon@wi.mit.edu> |
|---|---|
| date | Wed, 16 Apr 2014 11:35:55 -0400 |
| parents | eaa841a1f670 |
| children | d746f88add8b |
| files | ChangeLog doc/posix-functions/expl.texi m4/expl.m4 |
| diffstat | 3 files changed, 37 insertions(+), 0 deletions(-) [+] |
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--- a/ChangeLog Sat Apr 12 10:45:47 2014 -0700 +++ b/ChangeLog Wed Apr 16 11:35:55 2014 -0400 @@ -1,3 +1,9 @@ +2014-04-16 Assaf Gordon <agordon@wi.mit.edu> + + expl: avoid incorrect expl(small_value) on OpenBSD 5.4 + * m4/expl.m4 (gl_FUNC_EXPL): Add a check for this condition. + * doc/posix-functions/expl.texi: Mention the workaround. + 2014-04-12 Paul Eggert <eggert@cs.ucla.edu> xalloc: allow x2nrealloc (P, PN, S) where P && !*PN
--- a/doc/posix-functions/expl.texi Sat Apr 12 10:45:47 2014 -0700 +++ b/doc/posix-functions/expl.texi Wed Apr 16 11:35:55 2014 -0400 @@ -12,6 +12,9 @@ This function is missing on some platforms: FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, HP-UX 11, IRIX 6.5, Solaris 9, Cygwin, Interix 3.5, BeOS. @item +This function returns NaN for small operands: +OpenBSD 5.4. +@item This function is only defined as a macro with arguments on some platforms: MSVC 9. @item
--- a/m4/expl.m4 Sat Apr 12 10:45:47 2014 -0700 +++ b/m4/expl.m4 Wed Apr 16 11:35:55 2014 -0400 @@ -53,6 +53,34 @@ EXPL_LIBM=-lm fi fi + dnl On OpenBSD5.4 the system's native expl() is buggy: + dnl it returns 'nan' for small values. Test for this anomaly. + if test $gl_cv_func_expl_no_libm = yes \ + || test $gl_cv_func_expl_in_libm = yes; then + AC_CACHE_CHECK([whether expl() breaks with small values], + [gl_cv_func_expl_buggy], + [ + save_LIBS="$LIBS" + LIBS="$EXPL_LIBM" + AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [[#include <math.h>]], + [[return isnan(expl(-1.0))|| + isnan(expl(-0.8))|| + isnan(expl(-0.4)); ]])], + [gl_cv_func_expl_buggy=no], [gl_cv_func_expl_buggy=yes], + [case $host_os in + openbsd*) gl_cv_func_expl_buggy="guessing yes";; + *) gl_cv_func_expl_buggy="guessing no";; + esac]) + LIBS="$save_LIBS" + ]) + case "$gl_cv_func_expl_buggy" in + *yes) + gl_cv_func_expl_in_libm=no + gl_cv_func_expl_no_libm=no ;; + esac + fi if test $gl_cv_func_expl_no_libm = yes \ || test $gl_cv_func_expl_in_libm = yes; then dnl Also check whether it's declared.