frexp(Infinity) on IRIX 6.5 does not return Infinity, as it should according to
POSIX/MX. I'm adding a configure check against it:
2007-03-25 Bruno Haible <[EMAIL PROTECTED]>
* m4/frexp.m4 (gl_FUNC_FREXP_WORKS): Add check whether frexp(inf)
returns inf. Needed on IRIX 6.5.
*** m4/frexp.m4 22 Mar 2007 11:35:12 -0000 1.2
--- m4/frexp.m4 25 Mar 2007 21:19:53 -0000
***************
*** 1,4 ****
! # frexp.m4 serial 1
dnl Copyright (C) 2007 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
--- 1,4 ----
! # frexp.m4 serial 2
dnl Copyright (C) 2007 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
***************
*** 55,62 ****
fi
])
! dnl Test whether frexp() works also on denormalized numbers.
! dnl This test fails e.g. on NetBSD.
AC_DEFUN([gl_FUNC_FREXP_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
--- 55,62 ----
fi
])
! dnl Test whether frexp() works also on denormalized numbers (this fails e.g.
on
! dnl NetBSD 3.0) and on infinite numbers (this fails e.g. on IRIX 6.5).
AC_DEFUN([gl_FUNC_FREXP_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
***************
*** 70,75 ****
--- 70,76 ----
{
int i;
volatile double x;
+ /* Test on denormalized numbers. */
for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
;
if (x > 0.0)
***************
*** 81,91 ****
if (y != 0.5)
return 1;
}
return 0;
}], [gl_cv_func_frexp_works=yes], [gl_cv_func_frexp_works=no],
[case "$host_os" in
! netbsd*) gl_cv_func_frexp_works="guessing no";;
! *) gl_cv_func_frexp_works="guessing yes";;
esac
])
])
--- 82,100 ----
if (y != 0.5)
return 1;
}
+ /* Test on infinite numbers. */
+ {
+ x = 1.0 / 0.0;
+ int exp;
+ double y = frexp (x, &exp);
+ if (y != x)
+ return 1;
+ }
return 0;
}], [gl_cv_func_frexp_works=yes], [gl_cv_func_frexp_works=no],
[case "$host_os" in
! netbsd* | irix*) gl_cv_func_frexp_works="guessing no";;
! *) gl_cv_func_frexp_works="guessing yes";;
esac
])
])
