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