TMemoryStream.SaveToFile exceptions....

[Prime]

Hi all,

I'm writing a program to manipulate disk image files that will be used with retro computer emulators. My program loads the disk image into a TMemoryStream with LoadFromFile, does some operation on it, such as list, read or write files. Once the operation is complete, if it was a write it attempts to use SaveToFile to write it back to the disk file.

This unfortunately seems to lead to a EFCreateError about 25% of the time. The odd thing is if I retry the operation it will work. The file is not read only (as it was created initially by my program anyway). Also annoyingly if I run the program in Lazarus, single stepping it always works

My environment is Windows 7 x64, Lazarus 1.8.0. FPC 3.0.4. I don't currently have any addon components, so just a vanilla Lazarus install.

Anyone have any clues as to what is going on here?

My test batch file :

Code: Pascal  [Select][+][-]

1. dfsdisk create test.ssd -t 80 -q $20
2. dfsdisk write test.ssd -f ../System-ROM/FORM40 -q $20 -l $2800 -e $2800
3. dfsdisk write test.ssd -f ../System-ROM/FORM80 -q $20 -l $2800 -e $2800
4. dfsdisk write test.ssd -f ../System-ROM/VERIFY4 -q $20 -l $2800 -e $2800
5. dfsdisk write test.ssd -f ../System-ROM/VERIFY8 -q $20 -l $2800 -e $2800
6.  

My Test output :

Code: Pascal  [Select][+][-]

1. C:\Users\phill\Dropbox\AtomDOS\DFSDisk>test
2.  
3. C:\Users\phill\Dropbox\AtomDOS\DFSDisk>dfsdisk create test.ssd -t 80 -q $20
4. Created image file test.ssd, title , qual  , opt 0
5.  
6. C:\Users\phill\Dropbox\AtomDOS\DFSDisk>dfsdisk write test.ssd -f ../System-ROM/FORM40 -q $20 -l $2800 -e $2800
7. StreamIn.size=512
8. Saving to test.ssd
9. Wrote file ../System-ROM/FORM40 to DFS:FORM40  on image test.ssd
10.  
11. C:\Users\phill\Dropbox\AtomDOS\DFSDisk>dfsdisk write test.ssd -f ../System-ROM/FORM80 -q $20 -l $2800 -e $2800
12. StreamIn.size=512
13. Saving to test.ssd
14. Exception at 00411191: EFCreateError:
15. Unable to create file "test.ssd".
16.  
17. C:\Users\phill\Dropbox\AtomDOS\DFSDisk>dfsdisk write test.ssd -f ../System-ROM/VERIFY4 -q $20 -l $2800 -e $2800
18. StreamIn.size=294
19. Saving to test.ssd
20. Wrote file ../System-ROM/VERIFY4 to DFS:VERIFY4 on image test.ssd
21.  
22. C:\Users\phill\Dropbox\AtomDOS\DFSDisk>dfsdisk write test.ssd -f ../System-ROM/VERIFY8 -q $20 -l $2800 -e $2800
23. StreamIn.size=294
24. Saving to test.ssd
25. Exception at 00411191: EFCreateError:
26. Unable to create file "test.ssd".
27.  

Cheers.

Phill.

[rvk]

YIKES. C:\Users\phill\Dropbox\AtomDOS\DFSDisk

Did you try this OUTSIDE your dropbox?
When dropbox uploads changed files it will lock that file !!

(I've come across this myself  )

[Thaddy]

Indeed. Even your OS will - locally - lock that file... But the speed of the connection makes it visible. These are computing basics.

[Prime]

YIKES. C:\Users\phill\Dropbox\AtomDOS\DFSDisk

Did you try this OUTSIDE your dropbox?
When dropbox uploads changed files it will lock that file !!

(I've come across this myself  )

Ahhh yes of course, that makes sense, tried writing the file to c:\tmp\ and it works without problems. Glad to know it's not my code

Cheers.

Phill.