On IRIX 6.5 and mingw, the system function frexpf() has some of the bugs
that the frexp() also has. Here's the workaround:
2011-10-06 Bruno Haible <br...@clisp.org>
frexpf: Work around problems on IRIX and mingw.
* lib/math.in.h (frexpf): Consider also REPLACE_FREXPF.
* m4/math_h.m4 (gl_MATH_H_DEFAULTS): Initialize REPLACE_FREXPF.
* m4/frexpf.m4 (gl_FUNC_FREXPF_WORKS): New macro.
(gl_FUNC_FREXPF): Invoke it. Set REPLACE_FREXPF.
* modules/frexpf (Depends-on, configure.ac): Consider REPLACE_FREXPF.
* modules/math (Makefile.am): Substitute REPLACE_FREXPF.
* doc/posix-functions/frexpf.texi: Mention the IRIX and mingw problems.
--- doc/posix-functions/frexpf.texi.orig Fri Oct 7 00:58:44 2011
+++ doc/posix-functions/frexpf.texi Thu Oct 6 22:46:47 2011
@@ -10,10 +10,16 @@
@itemize
@item
This function is missing on some platforms:
-Minix 3.1.8, AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 9.
+Minix 3.1.8, AIX 5.1, HP-UX 11, Solaris 9.
@item
This function is only defined as a macro with arguments on some platforms:
MSVC 9.
+@item
+This function does not work on negative zero on some platforms:
+mingw.
+@item
+This function does not work on infinite numbers on some platforms:
+IRIX 6.5, mingw.
@end itemize
Portability problems not fixed by Gnulib:
--- lib/math.in.h.orig Fri Oct 7 00:58:44 2011
+++ lib/math.in.h Fri Oct 7 00:28:01 2011
@@ -343,11 +343,20 @@
If x is infinite or NaN: mantissa = x, exp unspecified.
Store exp in *EXPPTR and return mantissa. */
#if @GNULIB_FREXPF@
-# if !@HAVE_FREXPF@
-# undef frexpf
+# if @REPLACE_FREXPF@
+# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+# undef frexpf
+# define frexpf rpl_frexpf
+# endif
+_GL_FUNCDECL_RPL (frexpf, float, (float x, int *expptr) _GL_ARG_NONNULL ((2)));
+_GL_CXXALIAS_RPL (frexpf, float, (float x, int *expptr));
+# else
+# if !@HAVE_FREXPF@
+# undef frexpf
_GL_FUNCDECL_SYS (frexpf, float, (float x, int *expptr) _GL_ARG_NONNULL ((2)));
-# endif
+# endif
_GL_CXXALIAS_SYS (frexpf, float, (float x, int *expptr));
+# endif
_GL_CXXALIASWARN (frexpf);
#elif defined GNULIB_POSIXCHECK
# undef frexpf
--- m4/frexpf.m4.orig Fri Oct 7 00:58:44 2011
+++ m4/frexpf.m4 Fri Oct 7 00:56:43 2011
@@ -1,4 +1,4 @@
-# frexpf.m4 serial 2
+# frexpf.m4 serial 3
dnl Copyright (C) 2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -13,10 +13,81 @@
dnl exists, is defined in the same library as frexp(). This is not the case
dnl on NetBSD, OpenBSD.
gl_MATHFUNC([frexpf], [float], [(float, int *)])
- if test $gl_cv_func_frexpf_no_libm = no \
- && test $gl_cv_func_frexpf_in_libm = no; then
+ if test $gl_cv_func_frexpf_no_libm = yes \
+ || test $gl_cv_func_frexpf_in_libm = yes; then
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $FREXPF_LIBM"
+ gl_FUNC_FREXPF_WORKS
+ LIBS="$save_LIBS"
+ case "$gl_cv_func_frexpf_works" in
+ *yes) ;;
+ *) REPLACE_FREXPF=1 ;;
+ esac
+ else
HAVE_FREXPF=0
+ fi
+ if test $HAVE_FREXPF = 0 || test $REPLACE_FREXPF = 1; then
FREXPF_LIBM="$FREXP_LIBM"
fi
AC_SUBST([FREXPF_LIBM])
])
+
+dnl Test whether frexpf() works also on infinite numbers (this fails e.g. on
+dnl IRIX 6.5 and mingw) and on negative zero (this fails e.g. on mingw).
+AC_DEFUN([gl_FUNC_FREXPF_WORKS],
+[
+ AC_REQUIRE([AC_PROG_CC])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether frexpf works], [gl_cv_func_frexpf_works],
+ [
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#include <float.h>
+#include <math.h>
+#include <string.h>
+/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
+ ICC 10.0 has a bug when optimizing the expression -zero.
+ The expression -FLT_MIN * FLT_MIN does not work when cross-compiling
+ to PowerPC on MacOS X 10.5. */
+#if defined __hpux || defined __sgi || defined __ICC
+static float
+compute_minus_zero (void)
+{
+ return -FLT_MIN * FLT_MIN;
+}
+# define minus_zero compute_minus_zero ()
+#else
+float minus_zero = -0.0f;
+#endif
+int main()
+{
+ int result = 0;
+ volatile float x;
+ float zero = 0.0f;
+ /* Test on infinite numbers. */
+ x = 1.0f / zero;
+ {
+ int exp;
+ float y = frexpf (x, &exp);
+ if (y != x)
+ result |= 1;
+ }
+ /* Test on negative zero. */
+ x = minus_zero;
+ {
+ int exp;
+ float y = frexpf (x, &exp);
+ if (memcmp (&y, &x, sizeof x))
+ result |= 2;
+ }
+ return result;
+}]])],
+ [gl_cv_func_frexpf_works=yes],
+ [gl_cv_func_frexpf_works=no],
+ [case "$host_os" in
+ irix* | mingw*) gl_cv_func_frexpf_works="guessing no";;
+ *) gl_cv_func_frexpf_works="guessing yes";;
+ esac
+ ])
+ ])
+])
--- m4/math_h.m4.orig Fri Oct 7 00:58:44 2011
+++ m4/math_h.m4 Fri Oct 7 00:28:40 2011
@@ -1,4 +1,4 @@
-# math_h.m4 serial 29
+# math_h.m4 serial 30
dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -137,6 +137,7 @@
REPLACE_FLOOR=0; AC_SUBST([REPLACE_FLOOR])
REPLACE_FLOORF=0; AC_SUBST([REPLACE_FLOORF])
REPLACE_FLOORL=0; AC_SUBST([REPLACE_FLOORL])
+ REPLACE_FREXPF=0; AC_SUBST([REPLACE_FREXPF])
REPLACE_FREXP=0; AC_SUBST([REPLACE_FREXP])
REPLACE_FREXPL=0; AC_SUBST([REPLACE_FREXPL])
REPLACE_HUGE_VAL=0; AC_SUBST([REPLACE_HUGE_VAL])
--- modules/frexpf.orig Fri Oct 7 00:58:44 2011
+++ modules/frexpf Fri Oct 7 00:30:12 2011
@@ -8,11 +8,11 @@
Depends-on:
math
-frexp [test $HAVE_FREXPF = 0]
+frexp [test $HAVE_FREXPF = 0 || test $REPLACE_FREXPF = 1]
configure.ac:
gl_FUNC_FREXPF
-if test $HAVE_FREXPF = 0; then
+if test $HAVE_FREXPF = 0 || test $REPLACE_FREXPF = 1; then
AC_LIBOBJ([frexpf])
fi
gl_MATH_MODULE_INDICATOR([frexpf])
--- modules/math.orig Fri Oct 7 00:58:44 2011
+++ modules/math Fri Oct 7 00:29:02 2011
@@ -110,6 +110,7 @@
-e 's|@''REPLACE_FLOOR''@|$(REPLACE_FLOOR)|g' \
-e 's|@''REPLACE_FLOORF''@|$(REPLACE_FLOORF)|g' \
-e 's|@''REPLACE_FLOORL''@|$(REPLACE_FLOORL)|g' \
+ -e 's|@''REPLACE_FREXPF''@|$(REPLACE_FREXPF)|g' \
-e 's|@''REPLACE_FREXP''@|$(REPLACE_FREXP)|g' \
-e 's|@''REPLACE_FREXPL''@|$(REPLACE_FREXPL)|g' \
-e 's|@''REPLACE_HUGE_VAL''@|$(REPLACE_HUGE_VAL)|g' \
--
In memoriam Bahriye Üçok <http://en.wikipedia.org/wiki/Bahriye_Üçok>
