-# trunc.m4 serial 5
-dnl Copyright (C) 2007, 2010-2011 Free Software Foundation, Inc.
+# trunc.m4 serial 9
+dnl Copyright (C) 2007, 2010-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
dnl Persuade glibc <math.h> to declare trunc().
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
dnl Test whether trunc() is declared.
- AC_CHECK_DECLS([trunc], , , [#include <math.h>])
+ AC_CHECK_DECLS([trunc], , , [[#include <math.h>]])
if test "$ac_cv_have_decl_trunc" = yes; then
dnl Test whether trunc() can be used without libm.
TRUNC_LIBM=?
fi
m4_ifdef([gl_FUNC_TRUNC_IEEE], [
if test $gl_trunc_required = ieee && test $REPLACE_TRUNC = 0; then
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether trunc works according to ISO C 99 with IEC 60559],
[gl_cv_func_trunc_ieee],
[
#include <math.h>
]gl_DOUBLE_MINUS_ZERO_CODE[
]gl_DOUBLE_SIGNBIT_CODE[
-int main()
+static double dummy (double f) { return 0; }
+int main (int argc, char *argv[])
{
+ double (*my_trunc) (double) = argc ? trunc : dummy;
/* Test whether trunc (-0.0) is -0.0. */
- if (signbitd (minus_zerod) && !signbitd (trunc (minus_zerod)))
+ if (signbitd (minus_zerod) && !signbitd (my_trunc (minus_zerod)))
return 1;
return 0;
}
]])],
[gl_cv_func_trunc_ieee=yes],
[gl_cv_func_trunc_ieee=no],
- [gl_cv_func_trunc_ieee="guessing no"])
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_trunc_ieee="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_trunc_ieee="guessing no" ;;
+ esac
+ ])
LIBS="$save_LIBS"
])
case "$gl_cv_func_trunc_ieee" in
HAVE_DECL_TRUNC=0
fi
if test $HAVE_DECL_TRUNC = 0 || test $REPLACE_TRUNC = 1; then
- AC_LIBOBJ([trunc])
+ dnl No libraries are needed to link lib/trunc.c.
TRUNC_LIBM=
fi
AC_SUBST([TRUNC_LIBM])