From: Gennady Bystritsky <Gennady.Bystritsky@...>
Date: 2006-02-11T01:10:07+09:00
Subject: Re: Yet another question on exceptions

File.open is not that stupid ;-). It uses "ensure" internally to  close
a file in the case of exception. Using block with open guarantees that
the file will not remain open no matter what.

Gennady.

> -----Original Message-----
> From: Eric Jacoboni [mailto:jaco@neottia.net] 
> Sent: Friday, February 10, 2006 8:03
> To: ruby-talk ML
> Subject: Yet another question on exceptions
> 
> Hi,
> 
> If i use File::open to open/create a file objet, and if i use 
> a block with it, the file will be automatically close when 
> the block ends:
> 
> Now, considering this buggy snippet:
> 
> begin
>   File.open("my_file") do |fic|
>     fic.puts("bla")
>   end
> rescue Exception => e
>   STDERR.puts(e)
>   exit(1)
> end
> 
> Here, the "not opened for writing" exception will be raised, 
> the block end will never be reached and the file will remain 
> opened, isn't it ?
> To circumvent this, i have to make fic a global variable and 
> put the appropriate code in a ensure clause (or open a 
> begin/ensure in the File.open block to close the file... too bad)
> 
> So, my question is: what's the benefit of this idiom versus this one:
> 
> begin
>  fd = File.new("my_file")
>      ...
> rescue Exception => e
>   STDERR.puts(e)
>   exit(1)
> ensure
>  fd.close if fd and not fd.closed?
> end
> 
> Is there something i've missed?
> --
> Eric Jacoboni, ne il y a 1442972561 secondes
> 
>