assignment to substr as lvalue gives unexpected uninitialized warnings · Issue #5512 · Perl/perl5 · GitHub
Perl | substr関数の使い方(文字列の部分文字列を取得又は置換)
Use of PERL substr() Function
I am trying to build perl 5.18.2 on RedHat 8, I am using gcc 10.3.0. This test case is failing, and due to the issue with the Errno module, other tests are