--- /dev/null
+// ----------------------------------------------------------------------------
+// $Id$
+// ----------------------------------------------------------------------------
+// Public Domain C Library - http://pdclib.sourceforge.net
+// This code is Public Domain. Use, modify, and redistribute at will.
+// ----------------------------------------------------------------------------
+
+// ----------------------------------------------------------------------------
+// C++
+
+float copysign( float x, float y ) { /* TODO */ };
+long double copysign( long double x, long double y ) { /* TODO */ };
+
+// ----------------------------------------------------------------------------
+// Standard C
+
+double copysign( double x, double y ) { /* TODO */ };
+float copysignf( float x, float y ) { /* TODO */ };
+long double copysignl( long double x, long double y ) { /* TODO */ };