--- gsl-1.15.orig/complex/math.c	2010-12-26 18:57:08.000000000 +0100
+++ gsl-1.15/complex/math.c	2011-11-12 23:34:02.046480953 +0100
@@ -301,7 +301,7 @@ gsl_complex_sqrt (gsl_complex a)
       else
         {
           double ai = GSL_IMAG (a);
-          double vi = (ai >= 0) ? w : -w;
+          double vi = (signbit(ai)) ? -w : w;
           GSL_SET_COMPLEX (&z, ai / (2.0 * vi), vi);
         }
     }
@@ -537,6 +537,7 @@ gsl_complex_arcsin (gsl_complex a)
   if (I == 0)
     {
       z = gsl_complex_arcsin_real (R);
+      GSL_SET_IMAG (&z, copysign(GSL_IMAG(z), I));
     }
   else
     {
@@ -628,6 +629,7 @@ gsl_complex_arccos (gsl_complex a)
   if (I == 0)
     {
       z = gsl_complex_arccos_real (R);
+      GSL_SET_IMAG (&z, -copysign(GSL_IMAG(z), I));
     }
   else
     {
@@ -760,6 +762,7 @@ gsl_complex_arctan (gsl_complex a)
             {
               GSL_SET_COMPLEX (&z, 0, imag);
             };
+          GSL_SET_REAL (&z, copysign(GSL_REAL(z), R));
         }
       else
         {
@@ -936,7 +939,7 @@ gsl_complex
 gsl_complex_arccosh (gsl_complex a)
 {                               /* z = arccosh(a) */
   gsl_complex z = gsl_complex_arccos (a);
-  z = gsl_complex_mul_imag (z, GSL_IMAG(z) > 0 ? -1.0 : 1.0);
+  z = gsl_complex_mul_imag (z, signbit(GSL_IMAG(z)) ? 1.0 : -1.0);
   return z;
 }
 
@@ -967,17 +970,22 @@ gsl_complex_arccosh_real (double a)
 gsl_complex
 gsl_complex_arctanh (gsl_complex a)
 {                               /* z = arctanh(a) */
-  if (GSL_IMAG (a) == 0.0)
+  gsl_complex z;
+  double I = GSL_IMAG (a);
+
+  if (I == 0.0)
     {
-      return gsl_complex_arctanh_real (GSL_REAL (a));
+      z = gsl_complex_arctanh_real (GSL_REAL (a));
+      GSL_SET_IMAG (&z, copysign(GSL_IMAG(z), I));
     }
   else
     {
-      gsl_complex z = gsl_complex_mul_imag(a, 1.0);
+      z = gsl_complex_mul_imag(a, 1.0);
       z = gsl_complex_arctan (z);
       z = gsl_complex_mul_imag (z, -1.0);
-      return z;
     }
+
+  return z;
 }
 
 gsl_complex