Re: [Lazarus] Safe temp file name

[Aradeonas]

Thanks Graeme,Its like what I do so it seems Im doing OK. I looked at
the code and it seems it just remove { and }.
> if (LValue[1] = '{') and    (LValue[cGUIDLength] = '}') then    LValue
> := Copy(lValue, 2, cGUIDLength - 2);  AAssignTo.AsString := LValue;

It seems it doesnt remove "-" .

> This may be an appropriate use for EnterCriticalSection and
> ExitCriticalSection, although why don't you just use a different
> "prefix" in the call to GetTempFile for each thread.

Yes I can but GUID is easier to use.
> I wasn't aware that GetTempFileName isn't threadsafe.
(Are you sure your code is correct?) Yea. If you look at the
implementation it just check until there isnt a file so if 2 thread get
a filename before they create it it cause a problem. In my case I made
100 thread and they will create temp file and use them,simple but some
time it will happen.

> var
   GUID : TGUID; begin if CreateGUID(GUID) = 0 then begin  MyFileName :=
   GuiDToString(Guid); end;

Thanks.

Regards, Ara


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Re: [Lazarus] Safe temp file name

[Graeme Geldenhuys]

On 2015-11-25 15:27, Aradeonas wrote:
>> > if (LValue[1] = '{') and(LValue[cGUIDLength] = '}') thenLValue
>> > := Copy(lValue, 2, cGUIDLength - 2);  AAssignTo.AsString := LValue;
> It seems it doesnt remove "-" .
> 

Oops, my mistake. Yes, only { and } is removed in tiOPF code.

Regards,
  - Graeme -


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Re: [Lazarus] Safe temp file name

[Henry Vermaak]

On Wed, Nov 25, 2015 at 05:51:41AM -0800, Aradeonas wrote:
> Hi,
> 
> I used GetTempFileName in a multi thread system and it causes problems
> as you guess already. So the best way in my mind is using GUID and maybe
> use it in a loop for checking not existing for extra safety. But I want
> to know is there any clean implementation already that I dont know of?

It's pointless to check whether the file exists, since there's a race
between checking whether the file exists and creating/using it.

You need something that creates the file atomically only if it doesn't
exist.  For posix use open(2) with O_CREAT | O_EXCL.  For Windows use
CreateFile() with CREATE_NEW.  When this fails, try again with another
file name.

Henry

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Re: [Lazarus] Safe temp file name

[Rik van Kekem]

Graeme Geldenhuys wrote:

Oops, my mistake. Yes, only { and } is removed in tiOPF code.

Why are the { and } actually removed?

As far as I know they can be part of a filename on all OSes (or am I wrong?)

Grtz,
Rik (rvk)

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Re: [Lazarus] Safe temp file name

[Graeme Geldenhuys]

On 2015-11-25 15:41, Rik van Kekem wrote:
> Why are the { and } actually removed?
> 
> As far as I know they can be part of a filename on all OSes (or am I wrong?)

In tiOPF (the code I linked too), GUID's are used as an OID (Object ID),
and normally stored in a database field of type char(36). The { and }
was simply removed to save 2 bytes per record. I guess the "-" symbol
was left in place to make reading the OIDs (by a human) a bit easier -
most likely for debugging purposes only.

As for using the GUID value as a file name... I always followed the
example of tiOPF, but yes, modern file systems will allow the { and }
symbols in the file name without problem.

Regards,
  - Graeme -

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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[wkitty42]

On 11/25/2015 05:36 PM, Anthony Walter wrote:

Sweeet! For Linux users here is a complete FPC 3.0 release + Lazarus from svn
build script:

http://cache.getlazarus.org/download/linux/install-3.0.sh


without looking...

1. does this install to the system default or does it install to a user's home 
directory?


2. are there any prerequisites (like an existing system or user installation) 
necessary?


3. will this work with an existing fpcup installation? (my existing fpcup 
installation is broken and i've not had time to figure it all out again which 
generally results in blowing it all away and pulling it fresh all over again)


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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[Anthony Walter]

wkitty, I just updated the installers at:

http://www.getlazarus.org/setup/

It is built from FPC 3.0 now. It installs to your home folder without
needing any special rights to install.

Linux/Mac users can change the install folder by changing the $BASE
variable at the top of the script.

Windows users can just pick a folder in the installer program.

Lazarus and FPC configurations are read from their own directories and wont
interfere with other existing installations.
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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[Anthony Walter]

Sweeet! For Linux users here is a complete FPC 3.0 release + Lazarus from
svn build script:

http://cache.getlazarus.org/download/linux/install-3.0.sh
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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[Anthony Walter]

Joost, can you please remove the "experimental" tag next to the generic
bullet? I haven't seen any issues with them in quite a while.
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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[Gordon Cooper]

Same here, nobody home at that address.

Gordon.

On 11/26/2015 05:29 PM, Bee wrote:


> The 3.0.0 docs is available at
> http://www.freepascal.org/docs-html/3.0.0/fpctoc.htm

The doc can't be open. 404.

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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[Gordon Cooper]

Thank you.

G.



On 11/26/2015 08:31 PM, Michael Van Canneyt wrote:



On Thu, 26 Nov 2015, Vincent Snijders wrote:


2015-11-26 5:29 GMT+01:00 Bee :




The 3.0.0 docs is available at
http://www.freepascal.org/docs-html/3.0.0/fpctoc.htm


The doc can't be open. 404.



http://www.freepascal.org/docs-html/3.0.0/fpctoc.html


I created a symlink so it will open.

Michael.

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Re: [Lazarus] Safe temp file name

[Aradeonas]

Thank you Graeme. Can you point me to where this system
implemented in tiOPF?

Regards, Ara


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Re: [Lazarus] Safe temp file name

[Tony Whyman]

This may be an appropriate use for EnterCriticalSection and 
ExitCriticalSection, although why don't you just use a different 
"prefix" in the call to GetTempFile for each thread.


On 25/11/15 13:51, Aradeonas wrote:

Hi,
I used GetTempFileName in a multi thread system and it causes problems 
as you guess already.
So the best way in my mind is using GUID and maybe use it in a loop 
for checking not existing for extra safety.
But I want to know is there any clean implementation already that I 
dont know of?

Regards,
Ara
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Re: [Lazarus] Safe temp file name

[Rik van Kekem]

Aradeonas wrote:
> I used GetTempFileName in a multi thread system and it causes problems
> as you guess already.
I wasn't aware that GetTempFileName isn't threadsafe.
(Are you sure your code is correct?)

Graeme Geldenhuys wrote:

On 2015-11-25 13:51, Aradeonas wrote:

So the best way in my mind is using GUID and maybe
use it in a loop for checking not existing for extra safety.


So I think it is a pretty safe option to use as a temp file name, even
in a multi-threaded environment.


Even Microsoft advises it in case you use GetTempFileName excessively.
> Due to the algorithm used to generate file names, *GetTempFileName* 
can perform poorly when creating a large number of files with the same 
prefix. In such cases, it is recommended that you construct unique file 
names based on *GUID*s.

So it should be safe to use GUIDs for tempfilenames.

FPC trunk has this:
  Guid := TGUID.NewGuid.toString;

(I'm not sure if FPC 2.6.4 also some helpers for creating GUIDs)

Grtz,
Rik (rvk)

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Re: [Lazarus] Safe temp file name

[Rik van Kekem]

Rik van Kekem wrote:

(I'm not sure if FPC 2.6.4 also some helpers for creating GUIDs)


This will work in FPC 2.6.4:

var
  GUID : TGUID;
begin
  if CreateGUID(GUID) = 0 then
  begin
MyFileName := GuiDToString(Guid);
  end;

You could strip the {, } and - if you want.

Grtz,
Rik (rvk)

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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[Michael Van Canneyt]

On Thu, 26 Nov 2015, Vincent Snijders wrote:


2015-11-26 5:29 GMT+01:00 Bee :




The 3.0.0 docs is available at
http://www.freepascal.org/docs-html/3.0.0/fpctoc.htm


The doc can't be open. 404.



http://www.freepascal.org/docs-html/3.0.0/fpctoc.html


I created a symlink so it will open.

Michael.

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[Lazarus] Safe temp file name

[Aradeonas]

Hi,

I used GetTempFileName in a multi thread system and it causes problems
as you guess already. So the best way in my mind is using GUID and maybe
use it in a loop for checking not existing for extra safety. But I want
to know is there any clean implementation already that I dont know of?

Regards, Ara

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Re: [Lazarus] OmniPascal: Visual Studio Code Pascal Extension

[Michael Ring]

Dies it support Debugging?

Am 25.11.15 um 15:10 schrieb Anthony Walter:
In the event you haven't noticed, last week someone posted an 
announcement of a Free Pascal/Lazarus extension to Visual Studio Code:


http://www.omnipascal.com/

I installed it but so far I can't get the code insight working correctly.


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Re: [Lazarus] Safe temp file name

[Graeme Geldenhuys]

On 2015-11-25 13:51, Aradeonas wrote:
> So the best way in my mind is using GUID and maybe
> use it in a loop for checking not existing for extra safety.

I've used GUID's as temp file names in a CGI application for about 5
years. The CGI app gets accessed all at the same time in a classroom
environment by about 30-80 kids. I've never hit a duplicate GUID issue.
I'm not saying it is impossible, I'm just saying the chances are very
very slim.

In tiOPF I also use GUID's as Object ID's. I've multiple times imported
data which generates about 80,000-100,000 objects in memory in an
instant. Again, used this software for many years, and never hit a
single duplicate GUID.

So I think it is a pretty safe option to use as a temp file name, even
in a multi-threaded environment.

Regards,
  - Graeme -

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[Lazarus] OmniPascal: Visual Studio Code Pascal Extension

[Anthony Walter]

In the event you haven't noticed, last week someone posted an announcement
of a Free Pascal/Lazarus extension to Visual Studio Code:

http://www.omnipascal.com/

I installed it but so far I can't get the code insight working correctly.
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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[Bee]

> The 3.0.0 docs is available at
> http://www.freepascal.org/docs-html/3.0.0/fpctoc.htm

The doc can't be open. 404.

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Re: [Lazarus] FPC Pestering Peacock (3.0.0) release

[Vincent Snijders]

2015-11-26 5:29 GMT+01:00 Bee :

>
> > The 3.0.0 docs is available at
> > http://www.freepascal.org/docs-html/3.0.0/fpctoc.htm
>
> The doc can't be open. 404.
>

http://www.freepascal.org/docs-html/3.0.0/fpctoc.html

Vincent
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