problem with fwrite

[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 >.<...

[CPallini]

How did you check the file was not actually written? How did you define m_hkArr? How was HOTKEY defined? :)

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

[Cadimi]

I do it on Visual Studio 2005 SP1. I added config.pcm into my solution. After I had run my program, if config.pcm changed the content, then Visual Studio would ask you to update the content of that file. When I debug, I see the file pointer increase, but after I closed fout, VS didn't ask me to update the content -> the content hadn't been modified. m_hkArr is vector m_hkArr. The structure of struct HOTKEY: struct HOTKEY { BOOL isCtrl; UINT c; TCHAR szPath[256]; int id; //id of this hot key }; This struct is self-identified Hotkey :D. I just check for Ctrl or Alt is press with the key. id is the ID of the hotkey, return value of GlobalAddAtom. The code I have posted just a bit of my code

[CPallini]

Are you sure you're writing to the same file that is open by Visual Studio?

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

[Cadimi]

yes, When I change the config of my program, so, it have to write in the config.pcm. All the configurations of my program are written on config.pcm except for the hotkeys ( the bolded code )

[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

[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 >.<

[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

[Cadimi]

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

[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

[Cadimi]

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

[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

[Cadimi]

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

[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

[Cadimi]

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

[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

[Cadimi]

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

[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

[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

[David Crow]

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