read and write a file to a raspberry folder

2020-06-16
2020-11-01
  • pixtenduser2

    pixtenduser2 - 2020-06-16

    Dear programmers,

    I'm trying to write a programm, which reads and writes a config file to the raspberry pi filesystem.
    When I start the Pi, I want to read out the config and when I press a button ("save"), I want the programm to read out some variables and write them into the config file (.csv).
    I'm using the File Access library from 3S, but I can't get it to work.
    The problem is, that the function blocks "FILE.write" and "FILE.close don't work correctly in my setup.
    The eError outputs always return "handle invalid". I tried multiple settings for the csv-file (test.csv). I copied a valid version (filled with string data) of this file to the raspberry pi, I gave it the chmod 777 and 666 permissions, I let the programm create a new file and so on. But every time, I get "invalid handle". The FILE.open always returns a hfile (handle) with "0", and the write- and/or close-FB can't finish.
    If I copy a valid file to the raspberry, it has "0" size after opening and writing with my code.

    Can you explain me how I get to manage this problem? I would be very thankful for some advice.

    I added the code which I used:

    VAR
        bConfigWrite_Index : BYTE;
        xWriteConfig : BOOL;
        sTEST: STRING := 'TEST';
        FB_OpenFile : FILE.Open;
        FB_WriteFile : FILE.Write;
        FB_CloseFile : FILE.Close;
    
    
        xOpenFile : BOOL;
        xOpenFile_DONE : BOOL;
        xOpenConfig_Error : BOOL;
        eFileMode_Config : FILE.MODE;
        eError_Config : FILE.ERROR;
    
        xWriteFile : BOOL;
        xAbortFile : BOOL;
        xWriteFile_DONE : BOOL;
        xWriteConfig_Error : BOOL;
        eError_Write : FILE.ERROR;
    
        xCloseFile : BOOL;
        xCloseConfig_DONE : BOOL;
        xCloseConfig_Error : BOOL;
        eCloseConfig_Error : FILE.ERROR;
    END_VAR
    
    
    // PROGRAMM
    
    CASE bConfigWrite_Index OF
    
        0:  IF xWriteConfig THEN
                        xOpenFile := TRUE;
                        eFileMode_Config := File.MODE.MWRITE;
                        bConfigWrite_Index := 10;
                        xWriteConfig := FALSE;
            END_IF
    
    
        10: IF xOpenFile_DONE THEN
                        xOpenFile := FALSE;
                        bConfigWrite_Index := 20;
                END_IF
    
    
        20: xWriteFile := TRUE;
                bConfigWrite_Index := 21;
    
    
        21: IF xWriteFile_DONE THEN
                        xWriteFile := FALSE;
                        bConfigWrite_Index := 30;
                 END_IF
    
        30: xCloseFile := TRUE;
                bConfigWrite_Index := 40;
    
    
        40: IF xCloseConfig_DONE THEN
                        xCloseFile := FALSE;
                        bConfigWrite_Index := 0;
                 END_IF
    
    END_CASE
    
    
    FB_OpenFile(
            xExecute:= xOpenFile, 
            xDone=> xOpenFile_DONE, 
            xBusy=> , 
            xError=> xOpenConfig_Error, 
            sFileName:= '/home/pi/test/test.csv', 
            eFileMode:= eFileMode_Config, 
            xExclusive:= FALSE, 
            eError=> eError_Config, 
            hFile=> );
    
    FB_WriteFile(
                xExecute:= xWriteFile, 
                xAbort:= xAbortWrite, 
                udiTimeOut:= 100000, 
                xDone=> xWriteFile_DONE, 
                xBusy=> , 
                xError=> xWriteConfig_Error, 
                xAborted=> , 
                hFile:= FB_OpenFile.hFile, 
                pBuffer:= ADR(sTEST), 
                szSize:= SIZEOF(sTEST), 
                eError=> eError_Write);
    
    FB_CloseFile(
            xExecute:= xCloseFile, 
            xDone=> xCloseConfig_DONE, 
            xBusy=> , 
            xError=> xCloseConfig_Error, 
            hFile:= FB_OpenFile.hFile, 
            eError=> eCloseConfig_Error);
    
     
  • dvincent

    dvincent - 2020-11-01

    Hi,
    I want to do the same in XML , do you make it working ?

     

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