• llee <llee goucher.edu> Jul 30 2008
• BCS <ao pathlink.com> Jul 30 2008
• Sean Kelly <sean invisibleduck.org> Jul 30 2008
• "Koroskin Denis" <2korden gmail.com> Jul 30 2008
• llee <llee goucher.edu> Jul 30 2008
• Rakan Alhneiti <rakan.alhneiti nospam.gmail.com> Jul 30 2008

llee <llee goucher.edu> writes:

Is there any way to lock a file in D. I'm writing an application that needs to
support concurrent access to a file, and would like to lock the file during
write operations to prevent other process instances from reading invalid data.

BCS <ao pathlink.com> writes:

Reply to llee,

 Is there any way to lock a file in D. I'm writing an application that
 needs to support concurrent access to a file, and would like to lock
 the file during write operations to prevent other process instances
 from reading invalid data.
 


there may be some D library calls to do it (I haven't seen one, or looked) 
but if there isn't, you can always fall back on however you would do it in C.

Sean Kelly <sean invisibleduck.org> writes:

BCS wrote:
 Reply to llee,
 
 Is there any way to lock a file in D. I'm writing an application that
 needs to support concurrent access to a file, and would like to lock
 the file during write operations to prevent other process instances
 from reading invalid data.


 there may be some D library calls to do it (I haven't seen one, or 
 looked) but if there isn't, you can always fall back on however you 
 would do it in C.


On POSIX systems, file locking is purely cooperative.  There is no way 
to prevent users from opening your file if they so choose.  For this 
reason, I consider file locking largely useless beyond the scope of how 
a specific application behaves with respect to files it controls.


Sean

"Koroskin Denis" <2korden gmail.com> writes:

On Wed, 30 Jul 2008 20:14:59 +0400, llee <llee goucher.edu> wrote:

 Is there any way to lock a file in D. I'm writing an application that  
 needs to support concurrent access to a file, and would like to lock the  
 file during write operations to prevent other process instances from  
 reading invalid data.


In Tango, when you create a FileConduit you specify a Share attribute that  
affects concurrent file access policy:

enum Share : ubyte      {
     None=0,                 /// no sharing
     Read,                   /// shared reading
     ReadWrite,              /// open for anything
}

Is it what are you looking for?

llee <llee goucher.edu> writes:

Koroskin Denis Wrote:

 On Wed, 30 Jul 2008 20:14:59 +0400, llee <llee goucher.edu> wrote:
 
 Is there any way to lock a file in D. I'm writing an application that  
 needs to support concurrent access to a file, and would like to lock the  
 file during write operations to prevent other process instances from  
 reading invalid data.


 In Tango, when you create a FileConduit you specify a Share attribute that  
 affects concurrent file access policy:
 
 enum Share : ubyte      {
      None=0,                 /// no sharing
      Read,                   /// shared reading
      ReadWrite,              /// open for anything
 }
 
 Is it what are you looking for?


Looks good, but I'm using Phobos.

Rakan Alhneiti <rakan.alhneiti nospam.gmail.com> writes:

llee wrote:
 Koroskin Denis Wrote:
 
 On Wed, 30 Jul 2008 20:14:59 +0400, llee <llee goucher.edu> wrote:

 Is there any way to lock a file in D. I'm writing an application that  
 needs to support concurrent access to a file, and would like to lock the  
 file during write operations to prevent other process instances from  
 reading invalid data.


 affects concurrent file access policy:

 enum Share : ubyte      {
      None=0,                 /// no sharing
      Read,                   /// shared reading
      ReadWrite,              /// open for anything
 }

 Is it what are you looking for?


 Looks good, but I'm using Phobos.


being opened. it displays "Already in use" message. i wrote a program to 
lock files in vb6 years ago and it worked. Dont know about Linux and 
it's behavior on such thing