Update Gnulib; add new modules.

[bpt/guile.git] / m4 / trunc.m4

diff --git a/m4/trunc.m4 b/m4/trunc.m4
new file mode 100644 (file)
index 0000000..e106911
--- /dev/null
+++ b/m4/trunc.m4
@@ -0,0 +1,86 @@
+# trunc.m4 serial 5
+dnl Copyright (C) 2007, 2010-2011 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_TRUNC],
+[
+  m4_divert_text([DEFAULTS], [gl_trunc_required=plain])
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  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>])
+  if test "$ac_cv_have_decl_trunc" = yes; then
+    dnl Test whether trunc() can be used without libm.
+    TRUNC_LIBM=?
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#ifndef __NO_MATH_INLINES
+           # define __NO_MATH_INLINES 1 /* for glibc */
+           #endif
+           #include <math.h>
+           double x;]],
+         [[x = trunc(x);]])],
+      [TRUNC_LIBM=])
+    if test "$TRUNC_LIBM" = "?"; then
+      save_LIBS="$LIBS"
+      LIBS="$LIBS -lm"
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#ifndef __NO_MATH_INLINES
+             # define __NO_MATH_INLINES 1 /* for glibc */
+             #endif
+             #include <math.h>
+             double x;]],
+           [[x = trunc(x);]])],
+        [TRUNC_LIBM="-lm"])
+      LIBS="$save_LIBS"
+    fi
+    if test "$TRUNC_LIBM" = "?"; then
+      TRUNC_LIBM=
+    fi
+    m4_ifdef([gl_FUNC_TRUNC_IEEE], [
+      if test $gl_trunc_required = ieee && test $REPLACE_TRUNC = 0; then
+        AC_CACHE_CHECK([whether trunc works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_trunc_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $TRUNC_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_DOUBLE_MINUS_ZERO_CODE[
+]gl_DOUBLE_SIGNBIT_CODE[
+int main()
+{
+  /* Test whether trunc (-0.0) is -0.0.  */
+  if (signbitd (minus_zerod) && !signbitd (trunc (minus_zerod)))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_trunc_ieee=yes],
+              [gl_cv_func_trunc_ieee=no],
+              [gl_cv_func_trunc_ieee="guessing no"])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_trunc_ieee" in
+          *yes) ;;
+          *) REPLACE_TRUNC=1 ;;
+        esac
+      fi
+    ])
+  else
+    HAVE_DECL_TRUNC=0
+  fi
+  if test $HAVE_DECL_TRUNC = 0 || test $REPLACE_TRUNC = 1; then
+    AC_LIBOBJ([trunc])
+    TRUNC_LIBM=
+  fi
+  AC_SUBST([TRUNC_LIBM])
+])