On Friday, 4 May 2018 at 14:24:36 UTC, Vino wrote:
On Friday, 4 May 2018 at 14:02:24 UTC, Jonathan M Davis wrote:
On Friday, May 04, 2018 13:17:36 Vino via Digitalmars-d-learn
wrote:
On Friday, 4 May 2018 at 12:38:07 UTC, Adam D. Ruppe wrote:
> What are you actually trying to do with it? These functions
> are probably the wholly wrong approach.
Hi Adam,
The existing program in Windows do few task's eg: Delete
files
older that certain days, and now we are trying to port to
Linux,
and above was just a example, hence asked the right approach
for
porting.
Linux does not keep track of the creation time of a file. So,
it will not work to have a program on Linux ask a file how
long it's been since the file was created. If you want that
information, you'll have to store it elsewhere somehow (and
that generally only works if you created the file in the first
place).
The modification time of the file is the time that the file
was last changed (which would be the creation time if it were
only ever written to once, but in the general case, it has no
relation to the creation time at all). So, you could use
std.file.timeLastModified to find out if a file has been
changed within the last x number of days, but there is no way
to find out the creation time of a file by asking the
filesystem.
- Jonathan M Davis
Hi Jonathan,
Thank you, i got your point from the other forum topic which
was raised by me earlier, hence decided to use modification
time, the request is on how and the best approach to port the
code from windows to Linux eg program below
Example Code:
import std.stdio: writeln;
import std.container.array;
import std.file: dirEntries,isFile, SpanMode;
import std.algorithm: filter, map;
import std.typecons: Tuple, tuple;
import std.datetime.systime: SysTime;
version (Windows) { alias sTimeStamp = timeCreated; } else
version (linux) { alias sTimeStamp = timeLastAccessed; }
auto clogClean (string LogDir ) {
Array!(Tuple!(string, SysTime)) dFiles;
dFiles.insert(dirEntries(LogDir, SpanMode.shallow).filter!(a
=> a.isFile).map!(a => tuple(a.name, a.sTimeStamp)));
return dFiles;
}
void main () {
string LogDir;
LogDir = "//DScript/Test"; // Error: undefined
identifier timeLastAccessed on Linux
LogDir = "C:\\DScript\\Others"; // Error: undefined
identifier timeCreated on Windows.
writeln(clogClean(LogDir));
}
From,
Vino.B
Unlike NTFS for Windows there's a plethora of different file
systems available to use for Linux, one of which doesn't even
support deletion of files. You also have to keep in mind that
even if the same file system is used, there is no guarantee that
you have the same set of metadata available for a mount point
each and every time.
Consider a file system that's mounted with the 'noatime' option,
for instance, which doesn't log access times.
As far as I understand you are globing files, check times and
then act upon that.
If I were to port this to Linux, or any other OS for that matter,
I wouldn't depend on a feature of an OS.
Instead, since you have to look at a file either way to get the
meta data (which you query with the stat family of functions), I
would build my own database or cache with that information.
Glob the directory and add files not yet present with the current
date (and any other meta data you might need).
Then query all the files of interest and do whatever you want to
do with them and remove the entry.
Downside is you have possibly another dependency. On the plus
side you could easily query all files older than X days or
whatever with a single select and batch process them.
