Perl use vars pragma usage tips

Vars in perl is a pragma (precompiled indicator) in perl that is used to predefine global variables. These predefined global variables are in the qw () list, it can be used in the entire referenced perl file. Even if you use strict, no error is reported:

Copy codeThe Code is as follows: use strict;
$ Str = "hello world! \ N ";

Error message: Global symbol "$ str" requires explicit package name ~ Vars. pl line 3.
Execution ~ Vars. pl aborted due to complication errors.

Execute the result after referencing use vars:

Copy codeThe Code is as follows: use strict;
Use vars qw ($ str );
$ Str = "hello world! \ N ";
Print $ str;

Output:

Hello world!