Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Fast Get File Modification Time

Posted on 1998-05-27
7
Medium Priority
?
442 Views
Last Modified: 2013-12-03
Giving the path of a file, does anyone know a faster way to get the LastWrite time, than the following ?

// Try with GetFileTime, fast but I think it may fail if file is locked, but I haven't been able to provoke it

TimeFound = 0;
h = CreateFile(FileName, 0, FILE_SHARE_READ or FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
if (h >= 0) {
  if (GetFileTime(h, CreateTime, LastAccess, LastWrite)) {
   TimeFound = 1;
  }
}

if (!TimeFound) {
  // Get time using FindFirstFile, slow but don't care if file locked.
}
0
Comment
Question by:hustch
  • 3
  • 2
  • 2
7 Comments
 
LVL 22

Expert Comment

by:nietod
ID: 1404249
That looks like that should work well.  It shouldn't be too slow even when the FindFirstFile needs to be used.  

The "FILE_SHARE_READ or FILE_SHARE_WRITE" should be expressed as "FILE_SHARE_READ || FILE_SHARE_WRITE"  in C or C++, however.
0
 
LVL 23

Expert Comment

by:chensu
ID: 1404250
What do you mean by a faster way? One function call or faster speed?

If you are looking for one function call:

On Windows NT 4.0 or later, you can use the GetFileAttributesEx function to get the information.

You can also use FindFirstFile. But you have to use FindClose.

By the way, it should be | instead of ||.
0
 
LVL 22

Expert Comment

by:nietod
ID: 1404251
Opps.  Correct a mistake with a mistake.  Yes,

"FILE_SHARE_READ | FILE_SHARE_WRITE"

Chensu got me thinking too.  Looking at what you had I was lured into thinking that by opening the file with CreateFile() the OS would not have to search the directory tree and would therefore be faster.  That was stupid on my part.  The OS will still search, only it will do it on the open rather than on the procedure that gets the time.  In addition there is considerable overhead for opening and closing a file.  You are probably best off just using FindFirstFile (and associated procedures) in all cases.
0
Configuration Guide and Best Practices

Read the guide to learn how to orchestrate Data ONTAP, create application-consistent backups and enable fast recovery from NetApp storage snapshots. Version 9.5 also contains performance and scalability enhancements to meet the needs of the largest enterprise environments.

 
LVL 1

Author Comment

by:hustch
ID: 1404252
The or got there because it is actually Delphi code, that I translated because it is not the Delphi forum.
I know I have to use FindClose.

By faster, I mean shorter execution times.

The CreateFile is a lot faster, I don't know why, but I timed it. There is a lot of files in the directory.
The parameters to CreateFile was chosen in an attempt to avoid sharing problems.
I'll try GetFileAttributesEx
0
 
LVL 22

Expert Comment

by:nietod
ID: 1404253
There are probably plenty of people here who "speak" delphi, so you ussually shouldn't have to translate.

When you use FindFirstFile(), do you use a path that specifcally indicates the file?  You don't use wildcards and then look fo the file do you?
0
 
LVL 1

Author Comment

by:hustch
ID: 1404254
The GetFileAttirbutesEx is faster than the CreateFile approach.
It is what i wanted when I started, but I can't find using Delphi help, but I found it using MSVC++ help.

chensu, make an answer with GetFileAtttibutesEx, and I will accept it.
0
 
LVL 23

Accepted Solution

by:
chensu earned 400 total points
ID: 1404255
On Windows NT 4.0 or later, you can use the GetFileAttributesEx function to get the information.

Thank you.
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

With most software applications trying to cater to multiple user needs nowadays, the focus is to make them as configurable as possible. For e.g., when creating Silverlight applications which will connect to WCF services, the service end point usuall…
For a while now I'v been searching for a circular progress control, much like the one you get when first starting your Silverlight application. I found a couple that were written in WPF and there were a few written in Silverlight, but all appeared o…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
Is your data getting by on basic protection measures? In today’s climate of debilitating malware and ransomware—like WannaCry—that may not be enough. You need to establish more than basics, like a recovery plan that protects both data and endpoints.…

876 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question