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c++ / c confusion

开发者 https://www.devze.com 2023-01-03 18:19 出处:网络
Im trying to make a small app in c++ that saves midifiles with this library. http://musicnote.sourceforge.net/docs/html/index.html

Im trying to make a small app in c++ that saves midifiles with this library. http://musicnote.sourceforge.net/docs/html/index.html

The sample code that is given on the homepage looks like this.

 #include "MusicNoteLib.h"
    void ma开发者_运维问答in()
    {
        MusicNoteLib::Player player; // Create the Player Object
        player.Play("C D E F G A B"); // Play the Music Notes on the default MIDI output port
    }

This piece of code won't compile in Visual studio 2008, I get many errors like

MusicNoteLib.h(22) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

I don't understand the error or where to start looking... There also was some dll files that can be used instead of this h file.

    #ifndef __MUSICNOTE_LIB_H__EBEE094C_FF6E_43a1_A6CE_D619564F9C6A__
#define __MUSICNOTE_LIB_H__EBEE094C_FF6E_43a1_A6CE_D619564F9C6A__

/** @file MusicNoteLib.h
 * \brief Main header file for accessing the MusicNote Library
 */ 

/// <Summary>
/// This header file can be included directly in your project or through
/// MusicNoteLib.h of the MusicNoteDll project. If included directly, this
/// will be built directly as a satic library. If included through MusicNoteDll
/// this will use dllImports through MUSICNOTELIB_API
/// </Summary>
#ifndef MUSICNOTELIB_API
#define MUSICNOTELIB_API
#endif // MUSICNOTELIB_API

//#include "Player.h"

namespace MusicNoteLib /// Music Programming Library
{
typedef  void (__stdcall *LPFNTRACEPROC)(void* pUserData, const TCHAR* szTraceMsg);
typedef  void (__stdcall *LPFNERRORPROC)(void* pUserData, long lErrCode, const TCHAR* szErrorMsg, const TCHAR* szToken);

extern "C"
{
    MUSICNOTELIB_API typedef void MStringPlayer;

    MUSICNOTELIB_API void* GetCarnaticMusicNoteReader();

    /// <Summary>
    /// Creates a MusicString Player object.
    /// </Summary>
    MUSICNOTELIB_API MStringPlayer* CreateMusicStringPlayer();

    /// <Summary>
    /// Plays Music string notes on the default MIDI Output device with the default Timer Resolution.
    /// Use PlayMusicStringWithOpts() to use custom values.
    /// @param szMusicNotes the Music string to be played on the MIDI output device
    /// @return True if the notes were played successfully, False otherwise
    /// </Summary>
    MUSICNOTELIB_API bool PlayMusicString(const TCHAR* szMusicNotes);

    /// <Summary>
    /// Same as PlayMusicString() except that this method accepts Callbacks.
    /// The Trace and Error callbacks will be used during the Parse of the Music Notes.
    /// @param szMusicNotes the Music string to be played on the MIDI output device
    /// @param traceCallbackProc the Callback to used to report Trace messages
    /// @param errorCallbackProc the Callback to used to report Error messages
    /// @param pUserData any user supplied data that should be sent to the Callback
    /// @return True if the notes were played successfully, False otherwise
    /// </Summary>
    MUSICNOTELIB_API bool PlayMusicStringCB(const TCHAR* szMusicNotes,
                                            LPFNTRACEPROC traceCallbackProc, 
                                            LPFNERRORPROC errorCallbackProc, 
                                            void* pUserData);

    /// <Summary>
    /// Plays Music string notes on the given MIDI Output device using the given Timer Resolution.
    /// Use PlayMusicString() to use default values.
    /// @param szMusicNotes the Music notes to be played
    /// @param nMidiOutPortID the device ID of the MIDI output port to be used for the play
    /// @param nTimerResMS preferred MIDI timer resolution, in MilliSeconds
    /// @return True if Play was successful, False otherwise
    /// </Summary>
    MUSICNOTELIB_API bool PlayMusicStringWithOpts(const TCHAR* szMusicNotes, int nMidiOutPortID, unsigned int nTimerResMS);

    /// <Summary>
    /// Same as PlayMusicStringWithOpts() except that this method accepts Callbacks.
    /// The Trace and Error callbacks will be used during the Parse of the Music Notes.
    /// @param szMusicNotes the Music notes to be played
    /// @param nMidiOutPortID the device ID of the MIDI output port to be used for the play
    /// @param nTimerResMS preferred MIDI timer resolution, in MilliSeconds
    /// @param traceCallbackProc the Callback to used to report Trace messages
    /// @param errorCallbackProc the Callback to used to report Error messages
    /// @param pUserData any user supplied data that should be sent to the Callback
    /// @return True if Play was successful, False otherwise
    /// </Summary>
    MUSICNOTELIB_API bool PlayMusicStringWithOptsCB(const TCHAR* szMusicNotes, 
                                                    int nMidiOutPortID, 
                                                    unsigned int nTimerResMS,
                                                    LPFNTRACEPROC traceCallbackProc, 
                                                    LPFNERRORPROC errorCallbackProc, 
                                                    void* pUserData);
    /// <Summary>
    /// Save the given MusicString content into a MIDI output file
    /// @param szMusicNotes Music Notes to be converted to MIDI output
    /// @param szOutputFilePath path of the MIDI output file
    /// @return True if the the content was saved successfully, False otherwise
    /// </Summary>
    MUSICNOTELIB_API bool SaveAsMidiFile(const TCHAR* szMusicNotes, const char* szOutputFilePath);

    //MUSICNOTELIB_API typedef void (*ParseErrorProc)(const MusicNoteLib::CParser*, MusicNoteLib::CParser::ErrorEventHandlerArgs* pEvArgs);
    //MUSICNOTELIB_API typedef void (*ParseTraceProc)(const MusicNoteLib::CParser*, MusicNoteLib::CParser::TraceEventHandlerArgs* pEvArgs);

    MUSICNOTELIB_API void Parse(const TCHAR* szNotes, LPFNTRACEPROC traceCallbackProc, void* pUserData);

} // extern "C"



} // namespace MusicNoteLib

#endif // __MUSICNOTE_LIB_H__EBEE094C_FF6E_43a1_A6CE_D619564F9C6A__


The error is on this line:

typedef  void (__stdcall *LPFNTRACEPROC)(void* pUserData, const TCHAR* szTraceMsg);

It's been a while since I did C/C++ "in anger" so I'm a bit rusty here. There's a type mismatch somewhere - in fact as you spotted by wrapping the string in the _T macro.


You need to include the header(s) that declare LPFNTRACEPROC and TCHAR before you include MusicNoteLib.h in your CPP file. It could be Player.h which maybe shouldn't be commented out like ChrisF suggested, it could also be the Windows headers.

The basic idea is that you need to look at the lines the compiler is complaining about, figure out where the symbols on those lines are declared and include the appropriate header files that have those declarations.

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