Failure to reliably overwrite file from VBA - file

I have a VBA program that should delete and overwrite a file, with the same name. Code sample is below. Everything worked fine until maybe several months ago, when the overwrite started behaving strangely despite no apparent change anywhere. At times, the file was not overwritten at all. I then tried deleting the file manually before doing the write from VBA, that also didn't work, instead it looked like the previous version in the recycle bin was being restored, rather than overwriting my new version.
When I manually delete the file in the target folder, and also delete all previous revs from the recycle bin, the write works fine.
Posting this following a lot of googling and other searching, however nothing describes my specific problem. Any suggestions on what's happening here / how to fix?
Excel 2013 under Win10. Nothing unusual about the platform, the excel setup or the file being written, plenty of disk space available.
fname = "C:\DatFolder\Incrdat.bin"
Kill fname ' remove previous file
fnum = FreeFile
Open fname For Binary Access Write As #fnum
.... do write
Close #fnum
Edit 14 May, following many trials.
OMG how can this be so difficult??? :-/. I've put error checks on all the file ops, none occur. I've also added a 1-sec wait between the Kill and the file create. What happens now every time, is following the delete and rewrite, there is a file there again, but it's the previous file with the old timestamp. ie. Somehow the file that has been deleted is just put back as it was previously.
When I step through the code in debug, it works fine.
Many thanks for all the suggestions, but none of them have worked. I'm giving up and redoing the whole damn thing in C++, I know that'll work.
One more thing, unfortunately the suggestions to rewrite with a different file name, or to a different folder, can't be used unfortunately.

Related

Remove PDF password protection, knowing the password WINDOWS

I'd like to do something similar to Removing PDF password protection, knowing the password but in Windows. I have a folder with several PDFs that all have the same password, which I know. I would like to remove the password and overwrite the original files (don't worry, my data is a copy of another folder).
My thoughts are to use Autohotkey and create a script to open the file, paste the password, click enter, press Ctrl+P, click Print as PDF, save as the original file name, close Edge (which is what I'm using to open the PDFs), and then go to the next file in the folder.
I'm honestly not that familiar with AHK and would appreciate any help in what the code should be.
Thanks!
Edit: Here's some code I've tried but it doesn't seem to work.
^+q::
Loop %A_WorkingDir%\*.pdf
sleep 10000
Send, PASSWORD
sleep 2000
Send, {Enter}
Send, ^p
Click 105,694
WinClose, A
Return
When looping through files (using a files-loop as you have), it's not actually opening these but is giving you access to its OS-level properties, such as path, name, and system properties. You can use this information to open each one, using Run - something like, Run , %A_LoopFileLongPath%. Note that you may need to set Edge as your default PDF viewer if it isn't already.
Currently, your loop is only executing the line just beneath it, which is a 10-sec. sleep. You have 2,000 PDFs? That's about 5.5 hours of sleep before moving on. ;) If you want to execute more than one line, enclose it in braces { }, like so:
Loop , 1000
{
; stuff
}
From there, I would consider using WinWaitActive along with possibly ControlSend instead of Sleep and possibly Send. This will make your script more robust and may also take less time (assuming 10s is an upper bound). If at all possible, I would also discourage using clicks as these can sometimes be problematic (sometimes you have to send it multiple times for one click or locations might change). You can definitely make it work without these suggestions, it just might take more trial-and-error.
It may also be a good idea to build in a way to pause your script if needed, since this will likely take some time to do things to 2,000 files.
The help documentation is excellent and shows proper syntax and examples. I'd recommend consulting it for each of the commands.
https://www.autohotkey.com/docs/AutoHotkey.htm

changing and removing lines from text file using swi-prolog

I'm using text files as a database for saving users' information for a game which i made using swi-prolog. The information is saved like this:user(Name,Password,Age,Points). What i want to do is to change a user's Points without having to rewrite the entire db. In other words, I am looking for something that will work like retractall(user(Name,_,_,_)), but with the text file. I know how to find the specific user using read/2, and how to assert a new fact using write/2, but i don't know how to delete one specific line in the text file.
Thank you for helping.
Take a look at SWI-Prolog's library(persistency). It removes a fact by adding a line that the fact is removed. If the file gets too big with add/remove lines, it provides db_sync/1 to write a clean file. OS file system operations do not allow to remove part of a file (except from truncating the end). The normal way to do this is to write a new file and, if successful, rename this to the existing one, so nothing is lost if you crash while writing the new file.

AppleScript: "file is already open" but "file wasn't open"

Because of my slightly obsessive personality, I've been losing most of my productive time to a single little problem.
I recently switched from Mac OS X Tiger to Yosemite (yes, it's a fairly large leap). I didn't think AppleScript had changed that much, but I encountered a problem I don't remember having in the old days. I had the following code, but with a valid filepath:
set my_filepath to (* replace with string of POSIX filepath, because typing
colons was too much work *)
set my_file to open for access POSIX file my_filepath with write permission
The rest of the code had an error which I resolved fairly easily, but because the error stopped the script before the close access command, and of course AppleScript left the file reference open. So when I tried to run the script again, I was informed of a syntax error: the file is already open. This was to be expected.
I ran into a problem trying to close the reference: no matter what I did, I received an error message stating that the file wasn't open. I tried close access POSIX file (* filepath string again *), close access file (* whatever that AppleScript filepath format is called *), et cetera. Eventually I solved the problem by restarting my computer, but that's not exactly an elegant solution. If no other solution presents itself, then so be it; however, for intellectual and practical reasons, I am not satisfied with rebooting to close access. Does anyone have insights regarding this issue?
I suspect I've overlooked something glaringly obvious.
Edit: Wait, no, my switch wasn't directly from Tiger; I had an intermediate stage in Snow Leopard, but I didn't do much scripting then. I have no idea if this is relevant.
Agreed that restarting is probably the easiest solution. One other idea though is the unix utility "lsof" to get a list of all open files. It returns a rather large list so you can combine that with "grep" to filter it for you. So next time try this from the Terminal and see if you get a result...
lsof +fg | grep -i 'filename'
If you get a result you will get a process id (PID) and you could potentially kill/quit the process which is holding the file open, and thus close the file. I never tried it for this situation but it might work.
Have you ever had the Trash refuse to empty because it says a file is open? That's when I use this approach and it works most of the time. I actually made an application called What's Keeping Me (found here) to help people with this one problem and it uses this code as the basis for the app. Maybe it will work in this situation too.
Good luck.
When I've had this problem, it's generally sufficient to quit the Script editor and reopen it; a full restart of the machine is likely excessive. If you're running this from the Script Menu rather than Script Editor, you might try turning off the Script Menu (from Script Editor) and turning it back on again. The point is that files are held by processes, and if you quit the process it should release any lingering files pointers.
I've gotten into the habit, when I use open for access, of using try blocks to catch file errors. e.g.:
set filepath to "/some/posix/path"
try
set fp to open for access filepath
on error errstr number errnom
try
close access filepath
set fp to open for access filepath
on error errstr number errnom
display dialog errnum & ": " & errstr
end try
end try
This will try to open the file, try to close it and reopen it if it encounters and error, and report the error if it runs into more problems.
An alternative (and what I usually do) is that you can also comment out the open for access line and just add in a close access my_file to fix it.

permission denied for rename function in C on windows

I have an application developed in C. This application is supported across multiple platforms. There is one functionality where we are transferring files via file transfer protocol to different machine or to any other directory on local machine. I want to include a functionality where I can transfer the file with some temporary name and once the transfer is complete, I want to rename the file with the correct name (the actual file name).
I tried using simple rename() function. It works fine in Unix and Linux machines. But it does not work on Windows. It is giving me an error code of 13(Permission denied error).
First thing, I checked in msdn to know the functionality of rename if I have to grant some permissions to the file etc.
I granted full permissions to the file (lets say it is 777).
I read in few other posts that I should close the file descriptor before renaming the file. I did that too. It still gives the same error.
Few other posts mentioned about the owner of the file and that of the application. The application will run as a SYSTEM user. (But this should not affect the behavior, because I tried the same rename function in my application as follows:
This works fine from my application:
rename("C:/abc/aaa.txt","C:/abc/zzz.txt");
but
rename(My_path,"C:/abc/zzz.txt");
doesn't work, where My_path when printed displays C:/abc/test.txt.
How can I rename a file? I need it to work on multiple platforms.
Are there any other things I should be trying to make it work.?
I had this same problem, but the issue was slightly different. If I did the following sequence of function calls, I got "Permission Denied" when calling the rename function.
fopen
fwrite
rename
fclose
The solution was to close the file first, before doing the rename.
fopen
fwrite
fclose
rename
If
rename("C:/abc/aaa.txt","C:/abc/zzz.txt");
works but
rename(My_path,"C:/abc/zzz.txt");
does not, in the exact same spot in the program (i.e. replacing one line with another and making no changes), then there might be something wrong with the variable My_path. What is the type of this variable? If it is a char array (since this is C), is it terminated appropriately? And is it exactly equal to "C:/abc/aaa.txt"?
(I wish I could post this as a comment/clarification rather than as an answer but my rep isn't good enough :( )

stdio's remove() not always deleting on time

For a particular piece of homework, I'm implementing a basic data storage system using sequential files under standard C, which cannot load more than 1 record at a time. So, the basic part is creating a new file where the results of whatever we do with the original records are stored. The previous file's renamed, and a new one under the working name is created. The code's compiled with MinGW 5.1.6 on Windows 7.
Problem is, this particular version of the code (I've got nearly-identical versions of this floating around my functions) doesn't always remove the old file, so the rename fails and hence the stored data gets wiped by the fopen().
FILE *archivo, *antiguo;
remove("IndiceNecesidades.old"); // This randomly fails to work in time.
rename("IndiceNecesidades.dat", "IndiceNecesidades.old"); // So rename() fails.
antiguo = fopen("IndiceNecesidades.old", "rb");
// But apparently it still gets deleted, since this turns out null (and I never find the .old in my working folder after the program's done).
archivo = fopen("IndiceNecesidades.dat", "wb"); // And here the data gets wiped.
Basically, anytime the .old previously exists, there's a chance it's not removed in time for the rename() to take effect successfully. No possible name conflicts both internally and externally.
The weird thing's that it's only with this particular file. Identical snippets except with the name changed to Necesidades.dat (which happen in 3 different functions) work perfectly fine.
// I'm yet to see this snippet fail.
FILE *antiguo, *archivo;
remove("Necesidades.old");
rename("Necesidades.dat", "Necesidades.old");
antiguo = fopen("Necesidades.old", "rb");
archivo = fopen("Necesidades.dat", "wb");
Any ideas on why would this happen, and/or how can I ensure the remove() command has taken effect by the time rename() is executed? (I thought of just using a while loop to force call remove() again so long as fopen() returns a non-null pointer, but that sounds like begging for a crash due to overflowing the OS with delete requests or something.)
So suddenly, after reading Scott's mention of permissions, I thought about "Permission Denied" and applied some Google. Turned out it's a pretty common, if obscure, error.
caf was right, it was in another piece of code. Namely, I had forgotten to fclose that same file in the function meant to show the contents. Since I wasn't tracking that particular detail, it appeared to be random.
Disclaimer: Weekly math assigments make for very little sleeptime. ¬¬
That sounds quite strange, and even more so when you say that the same code works OK with a different filename - I would strongly suspect a bug elsewhere in your code. However, you should be able to work around it by renaming the file you want to remove:
rename("IndiceNecesidades.old", "IndiceNecesidades.older");
remove("IndiceNecesidades.older");
rename("IndiceNecesidades.dat", "IndiceNecesidades.old");
It would probably be a good idea to check the remove() function for errors. man remove says that the function returns 0 on success and -1 on failure, setting errno to record the error. Try replacing the call with
if (remove("IndiceNecesidades.old") != 0){
perror("remove(\"IndiceNecesidades.old\") failed");
}
which should give an error message saying what failed.
Further, it doesn't appear that the remove is neccessary
man rename()
The rename() system call causes the
link named old to be renamed as new.
If new exists, it is first removed.
Both old and new must be of the same
type (that is, both must be either
directories or non-directories) and
must reside on the same file system.
The rename() system call guarantees
that an instance of new will always
exist, even if the system should crash
in the middle of the operation.
If the final component of old is a
symbolic link, the symbolic link is
renamed, not the file or directory to
which it points.
EPERM will be returned if:
[EPERM] The directory
containing old is marked sticky, and
neither the containing directory nor
old are owned by the effective user
ID.
[EPERM] The new file
exists, the directory containing new
is marked sticky, and neither the
containing directory nor new are owned
by the effec-
tive user ID.
so the next step would be to check you have permissions on the containing directory

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