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-rw-r--r--sysdeps/generic/s_ctan.c74
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diff --git a/sysdeps/generic/s_ctan.c b/sysdeps/generic/s_ctan.c
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+/* Complex tangent function for double.
+ 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 Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <complex.h>
+#include <fenv.h>
+#include <math.h>
+
+#include "math_private.h"
+
+
+__complex__ double
+__ctan (__complex__ double x)
+{
+ __complex__ double res;
+
+ if (!isfinite (__real__ x) || !isfinite (__imag__ x))
+ {
+ if (__isinf (__imag__ x))
+ {
+ __real__ res = __copysign (0.0, __real__ x);
+ __imag__ res = __copysign (1.0, __imag__ x);
+ }
+ else if (__real__ x == 0.0)
+ {
+ res = x;
+ }
+ else
+ {
+ __real__ res = __nan ("");
+ __imag__ res = __nan ("");
+
+#ifdef FE_INVALID
+ if (__isinf (__real__ x))
+ feraiseexcept (FE_INVALID);
+#endif
+ }
+ }
+ else
+ {
+ double sin2rx, cos2rx;
+ double den;
+
+ __sincos (2.0 * __real__ x, &sin2rx, &cos2rx);
+
+ den = cos2rx + __ieee754_cosh (2.0 * __imag__ x);
+
+ __real__ res = sin2rx / den;
+ __imag__ res = __ieee754_sinh (2.0 * __imag__ x) / den;
+ }
+
+ return res;
+}
+weak_alias (__ctan, ctan)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__ctan, __ctanl)
+weak_alias (__ctan, ctanl)
+#endif