buffer problems with CFile

Krauze

This class is used to save the pix paths in the ListBox into a file. CListItemData is a class that stores additional info for every item in ListBox. This class operates correctly.

void CCfgFile::Serialize( const CListItemData& lid, const CListBox& lst )
{
loadConfigFile(); // a private funx which loads the file, it works correctly

fPic.Seek( sizeof( CONFIGFILE\_HEADER ), CFile::begin );
    // ommit the header section and move to the data

CString str;
int i = 0;
while( i < lst.GetCount() )
{
	// get the pic full path by combining the data in CListItemData and CListBox
	lst.GetText( i, str );
	str = lid.GetDir(i) + \_T("\\\\") + str + \_T(".") + lid.GetType(i);

	// initialize rcd, a structure for the file data
	memset( rcd.strPath, 0, sizeof( rcd.strPath ) );
	memset( rcd.nStyle, 0, sizeof( rcd.nStyle ) );
	
            // write the data into rcd structure
	strcpy( rcd.strPath, str );
	itoa( lid.GetStyle(i), rcd.nStyle, 10 );
	rcd.nStyle\[1\] = '\\0';
        
            // write the structure into file
	fPic.Write( &rcd, sizeof( CONFIGFILE\_RECORD ) );
	
            i++;
	
}

fPic.Close();

}

The prob occurs. Sometimes the file buffer is updated and the ListBox can show the updated data. But after I exit the proram, the disk file is not updated. This really confuses me. Even if I use CFile::Flush(), it's the same. Anyone could help me out? Really thanx.

hanq_38910130

I think there is not enough information about your problem in your post, so can you just provide some more information? Like definition of the struct type of "rcd"? Besides, maybe you can try to debug the application to find the reason of your problem:)

Iain Clarke Warrior Programmer

What is fPic? That's a pretty crucial bit of missing data... How is the file opened? Could it be failing on the opening (ie, already open elsewhere) and you're not handling the errors from a failed opening? Iain.

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Krauze

struct CONFIGFILE_RECORD
{
char strPath[MAX_PATH]; // the path of the pic
char nStyle[2]; // nStyle==0, IPIC_CENTER
// nStyle==1, IPIC_TILE
// nStyle==2, IPIC_STRETCH
}; // the record item of the config file

	// one more byte for the null terminator
	struct CONFIGFILE\_HEADER
	{
		char bHasPic\[2\];  // bHasPic==0, no pic paths are in the file
				  // bHasPic==1
		char bOrder\[2\];   // bOrder==1, the wallpaper is changed according to the set order
			          // bOrder==0, randomly
		char nTime\[5\];    // the interval for wallpaper changing
				  // max: 9000s = 2.5h
		char bEffect\[2\];  // bEffect==0, no special effect is used when the wallpaper is changing
				  // bEffect==1

		char nNum\[3\];    // the number of pix

		char nPos\[3\];    // the last position in the file that indicates a particular pic path
				 // 3 means this program supports up to 99 pics
	}; // the header of the configuration file

BOOL CCfgFile::loadConfigFile()
{
BOOL ret = FALSE;

// get the current dir
char dir\[MAX\_PATH\];
::GetCurrentDirectory( MAX\_PATH, dir );
strcat( dir, "\\\\config" );

UINT mode = CFile::modeCreate | CFile::modeNoTruncate | CFile::modeReadWrite | CFile::shareDenyNone;
if( fPic.m\_hFile )
	fPic.Close();
ret = fPic.Open( dir, mode );

if( !fPic.GetLength() )
{
	strcpy( hd.bHasPic, \_T("0") );
	strcpy( hd.bOrder, \_T("1") );
	strcpy( hd.nTime, \_T("9999") );
	strcpy( hd.bEffect, \_T("0") );
	strcpy( hd.nNum, \_T("0") );
	strcpy( hd.nPos, \_T("0") );
	fPic.Write( &hd, sizeof( CONFIGFILE\_HEADER ) );
} // some initializations if the file is not exised and created

return ret;

}

David Crow

You're first writing a CONFIGFILE_HEADER record to the file, rewinding it, and then writing one or more CONFIGFILE_RECORD records to it. :confused: Is that the intent?

Krauze wrote:

// get the current dir char dir[MAX_PATH]; ::GetCurrentDirectory( MAX_PATH, dir ); strcat( dir, "\\config" );

This will not always result in the same path.

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Vaclav_

Your ret is set to false and the return value from the file open is returned but never used in your main function.

Krauze

Thank y'all! I've got it solved with the help of DavidCrow. Actually, ::GetCurrentDirectory() may return inconsistent paths.