Posted: Tue Nov 24, 2020 12:46 am Post subject: Statement: SEEK #bFileNumber, NewPos
Has anyone tested SEEK as a statement (To set the file pointer to a desired location)?
I can't make it work even in a simple example:
Code:
If Sd_card_ready =1Then ' Open File
P_file_handle =Freefile()
File_name1 ="Test11.bin"'********************************************************************** PUT HERE THE DESIRED FILE NAME Open File_name1 ForBinaryAs #p_file_handle
' Set starting at position =20
Ltemp =20 Seek #p_file_handle , Ltemp
Print #1 , "Gbdoserror="; Gbdoserror
' Write data at position 20
Btemp1 =33 Put #p_file_handle , Btemp1
Print #1 , "Data_byte pos=";Loc(#p_file_handle)' This must be 20 but it is 1 ¿? ' ----------------------------------------------------------------- ' Save data to SD Card and close file ' Flush #p_file_handle ' flush to disk (This is not needed. The data is already flushed when Closing the file) Close #p_file_handle
' ----------------------------------------------------------------- End If
What I expected this code to print is:
Quote:
Test SD Card
SD Card OK
Filesystem = 11
Gbdoserror=0
Data_byte pos=20
However it prints the following when the file is created (the first time I run the program)
Quote:
Test SD Card
SD Card OK
Filesystem = 11
Gbdoserror=0
Data_byte pos=1 This should be 20!
After this, everytime I run the program with the file is already created in the SD card, it prints the following:
Test SD Card
SD Card OK
Filesystem = 11
Gbdoserror=97 This error is cpFilePositionError
Data_byte pos=1 This should be 20!
Notes:
- I have tried to create files, subdirectories, write content to files, Dir the files and everything seems to work fine. It is just a problem with Seek as stratement.
- I'm using a XMEGA192A3U
- The complete code is posted at the end of https://www.mcselec.com/index2.php?option=com_forum&Itemid=59&page=viewtopic&t=14714
- The SD card has been formatted with SD Card Formatter as suggested in BASCOM Help
- The card is a 4GB SDHC Card
- I have tried with a 16GB SDHC card and the result is the same, except that Filesystem = 12
The first step is always to read the help topic. In this case for SEEK.
It has an important note : In QB/VB you can use seek to make the file bigger. When a file is 100 bytes long, setting the file pointer to 200 will increase the file with 0 bytes. By design this is not the case in AVR-DOS.
So if you want to create files of certain size, you must do so explicit by writing to the file. _________________ Mark
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