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problem with fwrite

Scheduled Pinned Locked Moved C / C++ / MFC
helpdebugging
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  • CPalliniC CPallini

    Yes, I saw the code, anyway I was referring to you debugging actions (i.e. I didn't know if you stopped the program after few write operations). The reason behind my questions is I cannot believe fwrite silently failing, it never happened to me. Can't you isolate the failing piece of the writing routine and run it in a simpler context (for instance another, adhoc, project)?

    If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
    This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke

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    Cadimi
    wrote on last edited by
    #11

    thanks for your help, that's the worse thing I've ever met >.<

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    • C Cadimi

      I wrote a short code to write the status of my program to a file, but when debug in that code, I realize that fwrite function still increase its file pointer but when I read that file by fread function, I can't read that value. This is my code: // TODO: Add your control notification handler code here //write config file FILE *fout = fopen( "config.pcm", "wb" ); if ( fout ) { //write the time of power function fwrite( &m_uTime, sizeof( int ), 1, fout ); unsigned long temp; //write tasks //number of day task temp = m_alltasks.size(); fwrite( &temp, sizeof( long ), 1, fout ); for ( int i = 0; i < m_alltasks.size(); i++ ) { //date fwrite( &m_alltasks[i].date, sizeof( MYDATE ), 1, fout ); //number of notes in that day temp = m_alltasks[i].tasks.size(); fwrite( &temp, sizeof( long ), 1, fout ); //notes for ( int j = 0; j < m_alltasks[i].tasks.size(); j++ ) { fwrite( &m_alltasks[i].tasks[j], sizeof( TASK ), 1, fout ); } } //how many hotkeys have been defined temp = m_hkArr.size(); fwrite( &temp, sizeof( long ), 1, fout ); //write the list of hotkeys for ( int i = 0; i < temp; i++ ) fwrite( &m_hkArr[i], sizeof( HOTKEY ), 1, fout ); fclose( fout ); } else { MessageBox( _T( "Can't write config file" ), _T( "Warning" ) ); OnCancel(); } //unregister hotkeys for ( int i = 0; i < m_hkArr.size(); i++ ) { UnregisterHotKey( m_hWnd, m_hkArr[i].id ); GlobalDeleteAtom( m_hkArr[i].id ); } OnCancel(); They all work except for the code I bolded ( file pointer still increase, but the file is not change )... Help me plz >.<...

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      David Crow
      wrote on last edited by
      #12

      Cadimi wrote:

      FILE *fout = fopen( "config.pcm", "wb" );

      Are you using a relative path? What is the value of temp?

      "Love people and use things, not love things and use people." - Unknown

      "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

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      • D David Crow

        Cadimi wrote:

        FILE *fout = fopen( "config.pcm", "wb" );

        Are you using a relative path? What is the value of temp?

        "Love people and use things, not love things and use people." - Unknown

        "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

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        Cadimi
        wrote on last edited by
        #13

        temp is the number of hotkeys, its value is the size of the vector contain my HOTKEY struct

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        • C Cadimi

          temp is the number of hotkeys, its value is the size of the vector contain my HOTKEY struct

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          David Crow
          wrote on last edited by
          #14

          Cadimi wrote:

          temp is the number of hotkeys, its value is the size of the vector contain my HOTKEY struct

          I know what it represents. I asked what its value was (at the time of writing to the file).

          "Love people and use things, not love things and use people." - Unknown

          "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

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          • D David Crow

            Cadimi wrote:

            temp is the number of hotkeys, its value is the size of the vector contain my HOTKEY struct

            I know what it represents. I asked what its value was (at the time of writing to the file).

            "Love people and use things, not love things and use people." - Unknown

            "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

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            Cadimi
            wrote on last edited by
            #15

            I tried a simple example, its value at that time is 1

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            • C Cadimi

              I tried a simple example, its value at that time is 1

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              David Crow
              wrote on last edited by
              #16

              Ok, what do the two subsequent calls to fwrite() return?

              "Love people and use things, not love things and use people." - Unknown

              "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

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              • D David Crow

                Ok, what do the two subsequent calls to fwrite() return?

                "Love people and use things, not love things and use people." - Unknown

                "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

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                Cadimi
                wrote on last edited by
                #17

                I just watch the file pointer, it increase the value equal to the size I've requested to write on file

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                • C Cadimi

                  I just watch the file pointer, it increase the value equal to the size I've requested to write on file

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                  David Crow
                  wrote on last edited by
                  #18

                  But what do the two subsequent calls to fwrite() return?

                  "Love people and use things, not love things and use people." - Unknown

                  "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

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                  • D David Crow

                    But what do the two subsequent calls to fwrite() return?

                    "Love people and use things, not love things and use people." - Unknown

                    "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

                    C Offline
                    C Offline
                    Cadimi
                    wrote on last edited by
                    #19

                    I've found my problem :D... It happened when I ust CFileDialog in another code, select a path, then the default directory change too => write file at another place => can't read. Thanks for your help

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                    • C Cadimi

                      I've found my problem :D... It happened when I ust CFileDialog in another code, select a path, then the default directory change too => write file at another place => can't read. Thanks for your help

                      D Offline
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                      David Crow
                      wrote on last edited by
                      #20

                      Cadimi wrote:

                      ...can't read.

                      Which is why I was asking if fopen() was failing.

                      "Love people and use things, not love things and use people." - Unknown

                      "To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

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