Is there any way to detect the open error when using an anoymouns

Hello.

I would like to detect an open error when using an anonymous handler by designating the undefined scalar variable to open function.

How do I do?

This is a snip of code.
----------
open(my $fh, "non-exist-file");
unless (defined $fh) {
print "cannot open the file";
return;
}
----------

Best,
Takushi.

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Re: Is there any way to detect the open error when using an

Takushi Usami wrote:
> I would like to detect an open error when using an anonymous handle
> by designating the undefined scalar variable to open function.
> open(my $fh, "non-exist-file");
You can use the return value of open and the value of the error variables $=
! =

or $^E just as you normally would. See perldoc -f open and perldoc perlvar. =

FOr example:


C:\>perl -e "open my $file, '<', 'no such thingy' or die qq|Open: $^E\n|"
Open: The system cannot find the file specified

-- =

With kind regards Veli-Pekka Tätilä (vtatila@mail.student.oulu.fi)
Accessibility, game music, synthesizers and programming:
http://www.student.oulu.fi/~vtatila/ =


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RE: Is there any way to detect the open error when using an

Takushi Usami <> wrote:
> Hello.
> =

> I would like to detect an open error when using an anonymous handler
> by designating the undefined scalar variable to open function. =

> =

> How do I do?
> =

> This is a snip of code.
> ----------
> open(my $fh, "non-exist-file");
> unless (defined $fh) {
> print "cannot open the file";
> return;
> }
> ----------

First, it's a lexically scoped file handle, not anonymous, but
congratulations for using it. Second, the three argument form of open is
generally preferred these days. For example:

my $fn =3D "non-exist-file";
open my $fh, "<", $fn or die "Failed to open $fn: $!\n";

HTH

-- =

Brian Raven =


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Re: Is there any way to detect the open error when using

Brian Raven wrote:
>
> Second, the three argument form of open is
> generally preferred these days. For example:
>
> my $fn = "non-exist-file";
> open my $fh, "<", $fn or die "Failed to open $fn: $!\n";

Preferred by whom ? I don't think I've ever used it once. ;)

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RE: Is there any way to detect the open error when

Bill Luebkert <> wrote:
> Brian Raven wrote:
>> =

>> Second, the three argument form of open
>> is generally preferred these days. For example:
>> =

>> my $fn =3D "non-exist-file";
>> open my $fh, "<", $fn or die "Failed to open $fn: $!\n";
> =

> Preferred by whom ? I don't think I've ever used it once. ;)

I see it recommended on comp.lang.perl.misc quite often. I have been
using it fairly exclusively for at least a couple of years.

Sorry for not responding sooner, but I have been a little tied up
recently.

HTH

-- =

Brian Raven =


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registration no. 3962327. Registered office address at 25 Bank Street Lon=
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Re: Is there any way to detect the open error

Brian Raven wrote:
>
> I see it recommended on comp.lang.perl.misc quite often. I have been
> using it fairly exclusively for at least a couple of years.

Well, I take that with a grain of salt - I recommend using whatever
you number of args you like. ;)

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