Re: How to know a file is busy(read/write)?

FROM : Alastair Houghton
DATE : Fri Jan 11 15:53:34 2008

On 11 Jan 2008, at 05:19, shengjun_guan (ºÞÁn«T) wrote:

> Because i have one application to monitor one folder that files are 
> created in.
> eg. file1 and file2 have been created in the folder. My application 
> will send the file1 and file2
> to other application to open them.
> In some case, file1 have been finishing created.And file2 is 
> creating . So, if i send the tow files for
> opening to other application. file2 will open fail.
>
> So, i want to check the file2 if is busy before i send.


There is no such thing as a "busy" file on a UNIX system.  You need to 
redesign your application to work in a different way.  For instance, 
maybe files that your application acts on could have a different 
extension to the ones that are being created; renaming a file is an 
atomic operation, so once you've finished writing a file, you could 
then rename it to bring it to the attention of your other process.

If the source code is available for all the programs in question, you 
may also be able to use advisory locks, or lock files, or even some 
other mechanism (for instance, you could use a socket to send the 
names of the files to process to the far end).

Kind regards,

Alastair.

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