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-rw-r--r--math/s_nan.c44
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diff --git a/math/s_nan.c b/math/s_nan.c
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+++ b/math/s_nan.c
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+/* Return quiet nan.
+   Copyright (C) 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ieee754.h>
+
+
+double
+__nan (const char *tagp)
+{
+  if (tagp[0] != '\0')
+    {
+      char buf[6 + strlen (tagp)];
+      sprintf (buf, "NAN(%s)", tagp);
+      return strtod (buf, NULL);
+    }
+
+  return NAN;
+}
+weak_alias (__nan, nan)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__nan, __nanl)
+weak_alias (__nan, nanl)
+#endif