dynalink.h

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/*
 * dynalink.h
 *
 * Dynamic Link Library abstraction class.
 *
 * Portable Windows Library
 *
 * Copyright (c) 1993-1998 Equivalence Pty. Ltd.
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is Portable Windows Library.
 *
 * The Initial Developer of the Original Code is Equivalence Pty. Ltd.
 *
 * Portions are Copyright (C) 1993 Free Software Foundation, Inc.
 * All Rights Reserved.
 *
 * Contributor(s): ______________________________________.
 */

#ifndef PTLIB_DYNALINK_H
#define PTLIB_DYNALINK_H

#if !defined(P_RTEMS)

#ifdef P_USE_PRAGMA
#pragma interface
#endif

class PDynaLink : public PObject
{
  PCLASSINFO(PDynaLink, PObject);

  public:
    PDynaLink();
    PDynaLink(
      const PString & name    
    );

    ~PDynaLink();

    /* Open a new dyna-link, loading the specified module.
       The \p names string is a '\n' separated list of DLL names to attempt
       to load. The first one found is used.

       @return
       true if the library was loaded.
     */
    virtual PBoolean Open(
      const PString & names    
    );

    virtual void Close();

    virtual PBoolean IsLoaded() const;

    virtual PString GetName(
      PBoolean full = false  
    ) const;

    static PString GetExtension();

    typedef void (*Function)();


    PBoolean GetFunction(
      PINDEX index,           
      Function & func,        
      bool compulsory = false 
    );

    PBoolean GetFunction(
      const PString & name,  
      Function & func,        
      bool compulsory = false 
    );

    const PString & GetLastError() const { return m_lastError; }

    template <typename FuncPtr>
    class EntryPoint {
      protected:
        FuncPtr m_function;
      public :
        EntryPoint(
          PDynaLink & dll,
          const char * name,
          bool compulsory = true
        ) {
          Function fn;
          if (dll.GetFunction(name, fn, compulsory))
            m_function = reinterpret_cast<FuncPtr>(fn);
          else
            m_function = NULL;
        }

        bool IsPresent() const { return m_function != NULL; }
        operator FuncPtr() const { return PAssertNULL(m_function); }
    };
    #define P_DYNALINK_ENTRY_POINT(name) P_DISABLE_MSVC_WARNINGS(4355, name(*this, #name))
    #define P_DYNALINK_OPTIONAL_ENTRY_POINT(name) P_DISABLE_MSVC_WARNINGS(4355, name(*this, #name, false))

  protected:
    PString m_lastError;

// Include platform dependent part of class
#ifdef _WIN32
#include "msos/ptlib/dynalink.h"
#else
#include "unix/ptlib/dynalink.h"
#endif
};

#endif // !defined(P_RTEMS)


#endif //PTLIB_DYNALINK_H


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