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  4. problem with fwrite

problem with fwrite

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

    How can you see the file pointer advancing? How many HOTKEY items did you successfully write (i.e. Did you check temp value? Did you check fwrite return value?)? :)

    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

    C Offline
    C Offline
    Cadimi
    wrote on last edited by
    #7

    when debuging, just watch for the file pointer, so, I can see fout increase the value, I write 1 or 2 HOTKEY to try, but the content no change. When I read the file, the value is 0 >.<

    CPalliniC 1 Reply Last reply
    0
    • C Cadimi

      when debuging, just watch for the file pointer, so, I can see fout increase the value, I write 1 or 2 HOTKEY to try, but the content no change. When I read the file, the value is 0 >.<

      CPalliniC Offline
      CPalliniC Offline
      CPallini
      wrote on last edited by
      #8

      Cadimi wrote:

      I write 1 or 2 HOTKEY to try

      But then do you close the file?

      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

      In testa che avete, signor di Ceprano?

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      • CPalliniC CPallini

        Cadimi wrote:

        I write 1 or 2 HOTKEY to try

        But then do you close the file?

        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

        C Offline
        C Offline
        Cadimi
        wrote on last edited by
        #9

        as you can see in the code, I closed it, and before closed it, I fflush( fout ) carefully :D

        CPalliniC 1 Reply Last reply
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        • C Cadimi

          as you can see in the code, I closed it, and before closed it, I fflush( fout ) carefully :D

          CPalliniC Offline
          CPalliniC Offline
          CPallini
          wrote on last edited by
          #10

          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

          In testa che avete, signor di Ceprano?

          C 1 Reply Last reply
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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

            C Offline
            C Offline
            Cadimi
            wrote on last edited by
            #11

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

            1 Reply Last reply
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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 >.<...

              D Offline
              D Offline
              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

              C 1 Reply Last reply
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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

                C Offline
                C Offline
                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

                D 1 Reply Last reply
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                • C Cadimi

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

                  D Offline
                  D Offline
                  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

                  C 1 Reply Last reply
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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

                    C Offline
                    C Offline
                    Cadimi
                    wrote on last edited by
                    #15

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

                    D 1 Reply Last reply
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                    • C Cadimi

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

                      D Offline
                      D Offline
                      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

                        C Offline
                        C Offline
                        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

                          D Offline
                          D Offline
                          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

                          C 1 Reply Last reply
                          0
                          • 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

                            D 1 Reply Last reply
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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
                              D Offline
                              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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