Get File Size

[Oliver Twesten]

Hi

What is the fastest way to retrieve the (64 bit) filesize of a file?

I need to get the size of *many* files from various locations (on WinXP systems,only), so what would be faster:

CreateFile + GetFileSize + CloseHandle
or
FindFirstFile / FindNextFile

or do you have another idea?

Thank you in advance.

Oliver.

[SOCM_FP_CPP]

hi,
FindFirstFile/FindNextFile/FindClose seems to be the fastest and
preferred ...IMHO


Praseed Pai

[Ejaz]

Although I haven't used any of them so far, but they look handy for this purpose.
GetFileSize
GetCompressedFileSize
GetFileSizeEx

[genossa]

You can also try GetFileAttributesEx ().

I'm not sure whether it is faster than FindFirst/FindNext/FindClose, but it is definitely faster than CreateFile/GetFileSize (which also modifies the file last access time).

[Oliver Twesten]

Thank you for your suggestions!

@Ejaz
But GetFileSize etc. require that the file was previously opened by a call to CreateFile. This is the API I'm currently using, but it seems a little slow to me.

@genossa
Bingo! I knew there was a function which takes the file path and returns the 64bit file size, but I could not remember what it was. I believe this will be much faster, so I'll try it next week and post the results of my little test

Thank you all & have a good weekend.

Oliver.

[Marc G]

I use _stat64 which accepts a filename and which retrieves a 64 bit size.

[Oliver Twesten]

I just tried GetFileAttributesEx(...) and it really seems to be *much* faster than GetFileSize(...)!

The only drawback is that GetFileAttributesEx(...) is not supported by Win95.

@Marc G
Thank you; I didn't knew this C runtime function (_stati64, _wstati64). I'll give them a try and report back!

Oliver.

[Oliver Twesten]

I use _stat64 which accepts a filename and which retrieves a 64 bit size.

At least on my Win2k workstation, _stati64 is screaming fast compared to CreateFile / GetFileSize / CloseFile!

Maybe it is a drawback that it does not support security attributes, but I do not need that anyway.

Thank you for this tip!

Oliver.

[genossa]

One more tip:

_stat64 uses FindFirstFile/FindClose inside (just looked into the source code of
_stat64 for Visual Studio). So, if your application is designed for Windows paltform then using FindFirstFile/FindClose directly will be a little bit faster than calling to _stat64

[Oliver Twesten]

Hi genossa

Where did you look it up? I just searched the MS VC directory and the web but did not find the implementation of stati64.

BTW: The function names are _stati64 and _wstati64().

Oliver.

[Oliver Twesten]

Oh, I just found it: VC98\CRT\SRC\STAT.C function declaration "int __cdecl _tstati64".

It really uses FindFirstFile / FindClose API. I must say that I did not believe these APIs are that fast!

Thank you.

Oliver.

[SOCM_FP_CPP]

Hi ,

on my machine i have installed VS.net in the C folder.

u may find the source code of the routines mentioned above in the following path
C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\crt\src

Praseed Pai
www.praseedpai.com

[genossa]

BTW: The function names are _stati64 and _wstati64().

Oops. My bad.