> 2012-02-29 Bruno Haible <br...@clisp.org>
>
> New module 'cbrtl'.
> * lib/math.in.h (cbrtl): New declaration.
> * lib/cbrtl.c: New file.
> * m4/cbrtl.m4: New file.
> * m4/math_h.m4 (gl_MATH_H): Test whether cbrtl is declared.
> (gl_MATH_H_DEFAULTS): Initialize GNULIB_CBRTL, HAVE_CBRTL,
> HAVE_DECL_CBRTL.
> * modules/math (Makefile.am): Substitute GNULIB_CBRTL, HAVE_CBRTL,
> HAVE_DECL_CBRTL.
> * modules/cbrtl: New file.
> * tests/test-math-c++.cc: Check the declaration of cbrtl.
> * doc/posix-functions/cbrtl.texi: Mention the new module.
The tests fail on OpenBSD 5.1/SPARC:
test-cbrt.h:39: assertion failed
FAIL: test-cbrtl
cbrtl(16.0L) returns 1.2599..., which is obviously completely broken.
Here's the workaround:
2012-03-13 Bruno Haible <br...@clisp.org>
cbrtl: Bypass broken implementation in OpenBSD 5.1/SPARC.
* m4/cbrtl.m4 (gl_FUNC_CBRTL_WORKS): New macro.
(gl_FUNC_CBRTL): Invoke it. If the function does not work, set
REPLACE_CBRTL to 1.
* doc/posix-functions/cbrtl.texi: Mention the OpenBSD 5.1/SPARC bug.
--- doc/posix-functions/cbrtl.texi.orig Wed Mar 14 00:36:43 2012
+++ doc/posix-functions/cbrtl.texi Wed Mar 14 00:28:42 2012
@@ -14,6 +14,9 @@
@item
This function is not declared on some platforms:
IRIX 6.5.
+@item
+This function produces grossly wrong results on some platforms:
+OpenBSD 5.1/SPARC.
@end itemize
Portability problems fixed by Gnulib module @code{cbrtl-ieee}:
--- m4/cbrtl.m4.orig Wed Mar 14 00:36:43 2012
+++ m4/cbrtl.m4 Wed Mar 14 00:33:31 2012
@@ -1,4 +1,4 @@
-# cbrtl.m4 serial 3
+# cbrtl.m4 serial 4
dnl Copyright (C) 2012 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -25,6 +25,16 @@
dnl Also check whether it's declared.
dnl IRIX 6.5 has cbrtl() in libm but doesn't declare it in <math.h>.
AC_CHECK_DECL([cbrtl], , [HAVE_DECL_CBRTL=0], [[#include <math.h>]])
+
+ save_LIBS="$LIBS"
+ LIBS="$LIBS $CBRTL_LIBM"
+ gl_FUNC_CBRTL_WORKS
+ LIBS="$save_LIBS"
+ case "$gl_cv_func_cbrtl_works" in
+ *yes) ;;
+ *) REPLACE_CBRTL=1 ;;
+ esac
+
m4_ifdef([gl_FUNC_CBRTL_IEEE], [
if test $gl_cbrtl_required = ieee && test $REPLACE_CBRTL = 0; then
AC_CACHE_CHECK([whether cbrtl works according to ISO C 99 with IEC
60559],
@@ -95,3 +105,40 @@
fi
AC_SUBST([CBRTL_LIBM])
])
+
+dnl Test whether cbrtl() works.
+dnl On OpenBSD 5.1/SPARC, cbrtl(16.0L) is = 1.2599...
+AC_DEFUN([gl_FUNC_CBRTL_WORKS],
+[
+ AC_REQUIRE([AC_PROG_CC])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+ AC_CACHE_CHECK([whether cbrtl works], [gl_cv_func_cbrtl_works],
+ [
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
+#include <math.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+long double cbrtl (long double);
+volatile long double x;
+long double y;
+int main ()
+{
+ x = 16.0L;
+ y = cbrtl (x);
+ if (y < 2.0L)
+ return 1;
+ return 0;
+}
+]])],
+ [gl_cv_func_cbrtl_works=yes],
+ [gl_cv_func_cbrtl_works=no],
+ [case "$host_os" in
+ osf*) gl_cv_func_cbrtl_works="guessing no";;
+ *) gl_cv_func_cbrtl_works="guessing yes";;
+ esac
+ ])
+ ])
+])
