When did file mode in Perl open become a separate argument?

Question

Once you opened files in Perl, for example:

open(FH, ">$filename"); 

At some point, for many reasons, including some very sticky ones that contain file names with leading spaces, this syntax became available (and, immediately, preferred):

 open(FH, '>', $filename); 

In what version of Perl did we get this syntax with?

Answer 1

When you have questions like this, start scanning through perl * delta documents. You can mostly skip minor versions, since these versions should not introduce basic functions.

In this case, you will find it in perl56delta .

Answer 2

It looks like 5.6.0 .