Function CPPDemangle(name as string) As string
  //! Demangles a C++ function name. Returns an empty string on failure.
  //! Only works on Mac OS X.
 
  #if targetMacOS
      declare function __cxa_demangle lib "/usr/lib/libstdc++.6.dylib" ( name as CString, _
      outBuffer as ptr, outLength as ptr, byref outState as integer ) as CString
    declare sub free lib "System" ( value as CString )
    const kStateSuccess = 0
 
    dim state as integer
    dim demangledString as CString = __cxa_demangle( name, nil, nil, state )
 
    if state = kStateSuccess then
      // create our RB string, then free the string demangle gave us
      dim result as string = demangledString
      free( demangledString )
 
      return result
    end if
  #endif
End Function

Function GetErrorStack(err as RuntimeException) As string()
  //! Gets the stack trace for our exception. This differs from
 //! RuntimeException.stack in that it demangles C++ names.
 
  // this can crash in some cases, giving us a completely useless crash log
  // <rb-feedback://keeqghwg>, hopefully this will be fixed someday...
  dim stack() as string = err.stack
  dim cleanedStack() as string
 
  // the order of RB's "for each" isn't defined <rb-feedback://hdcdbgfi>, so we have
  // to use a normal loop
  for i as integer = 0 to stack.ubound
    dim name as string = stack( i )
    dim demangledName as string = cppDemangle( name )
 
    if demangledName <> "" then
      cleanedStack.append( demangledName )
    else
      cleanedStack.append( name )
    end if
  next
 
  return cleanedStack
End Function

#include <stdarg.h>
 
void* GetInstanceMethodAddr(char x, ...) {
	va_list argp;
	void *addr;
 
	va_start(argp, x);
	addr = va_arg(argp, void *);
	va_end(argp);
 
	return addr;
}
 
// For example,
void *func = GetInstanceMethodAddr(42, &std::string::size);