+// ----------------------------------------------------------------------------
+// $Id$
+// ----------------------------------------------------------------------------
+// Public Domain C Library - http://pdclib.sourceforge.net
+// This code is Public Domain. Use, modify, and redistribute at will.
+// ----------------------------------------------------------------------------
+
+// ----------------------------------------------------------------------------
+// C++
+
+double arg( double _Complex x ) { /* TODO */ };
+float arg( float _Complex x ) { /* TODO */ };
+long double arg( long double _Complex x ) { /* TODO */ };
+float carg( float _Complex x ) { /* TODO */ };
+long double carg( long double _Complex x ) { /* TODO */ };
+
+// ----------------------------------------------------------------------------
+// Standard C
+
+double carg( double _Complex x ) { /* TODO */ };
+float cargf( float _Complex x ) { /* TODO */ };
+long double cargl( long double _Complex x ) { /* TODO */ };