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open(my $fh, '>', $path) || die $!; my_sub($fh); Can my_sub() somehow extrapolate $path from $fh?
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The three basic FileHandles in Perl are STDIN, STDOUT, and STDERR, which represent Standard Input, Standard Output, and Standard Error devices respectively. File Handling is usually done through the open function. Syntax: open(FileHandle, Mode, FileName);
You use open() function to open files. The open() function has three arguments: Filehandle that associates with the file. Mode : you can open a file for reading, writing or appending.
The $fh (file handle) is a scalar variable and we can define it inside or before the open() function. Here we have define it inside the function. The '>' sign means we are opening this file for writing. The $filename denotes the path or file location. Once file is open, use $fh in print statement.
A filehandle might not even be connected to a file but instead to a network socket or a pipe hooked to the standard output of a child process.
If you want to associate handles with paths your code opens, use a hash and the fileno operator, e.g.,
my %fileno2path; sub myopen { my($path) = @_; open my $fh, "<", $path or die "$0: open: $!"; $fileno2path{fileno $fh} = $path; $fh; } sub myclose { my($fh) = @_; delete $fileno2path{fileno $fh}; close $fh or warn "$0: close: $!"; } sub path { my($fh) = @_; $fileno2path{fileno $fh}; } Whoever might be looking for better way to find the file name from filehandle or file descriptor:
I would prefer to use the find -inum , if available. Or, how about using following way, always - any drawbacks except the unix/linux compatible!
my $filename='/tmp/tmp.txt'; open my $fh, '>', $filename; my $fd = fileno $fh; print readlink("/proc/$$/fd/$fd"); If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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