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-rw-r--r--sysdeps/generic/s_ctan.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/sysdeps/generic/s_ctan.c b/sysdeps/generic/s_ctan.c
index 6a09fe465b..0464ab86d5 100644
--- a/sysdeps/generic/s_ctan.c
+++ b/sysdeps/generic/s_ctan.c
@@ -1,5 +1,5 @@
/* Complex tangent function for double.
- Copyright (C) 1997 Free Software Foundation, Inc.
+ Copyright (C) 1997, 2005 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
@@ -61,8 +61,18 @@ __ctan (__complex__ double x)
den = cos2rx + __ieee754_cosh (2.0 * __imag__ x);
- __real__ res = sin2rx / den;
- __imag__ res = __ieee754_sinh (2.0 * __imag__ x) / den;
+ if (den == 0.0)
+ {
+ __complex__ double ez = __cexp (1.0i * x);
+ __complex__ double emz = __cexp (-1.0i * x);
+
+ res = (ez - emz) / (ez + emz) * -1.0i;
+ }
+ else
+ {
+ __real__ res = sin2rx / den;
+ __imag__ res = __ieee754_sinh (2.0 * __imag__ x) / den;
+ }
}
return res;