Unix Programming - Why do I get Q

Author

Why do I get Q

Ian Pellew

2004-11-19, 8:57 pm

Hi All;

Why am I getting the perl -W complaint like:-
[Thu Nov 18 22:44:07 2004] w: Useless use of a constant in void
context at w line 208.
[Thu Nov 18 22:44:07 2004] w: Useless use of a constant in void
context at w line 397.
. . . . .

from the likes of :-
199: my $xml;
200: $xml = get_pg_dir() . . . . . .;
208: $db?print qq(Tags file = '$xml'\n):"";

I use $xml a lot later in the process.

Regards
Ian

Måns Rullgård

2004-11-19, 8:57 pm

ipellew@pipemedia.co.uk (Ian Pellew) writes:

> Hi All;
>
> Why am I getting the perl -W complaint like:-
> [Thu Nov 18 22:44:07 2004] w: Useless use of a constant in void
> context at w line 208.
> [Thu Nov 18 22:44:07 2004] w: Useless use of a constant in void
> context at w line 397.
> . . . . .
>
> from the likes of :-
> 199: my $xml;
> 200: $xml = get_pg_dir() . . . . . .;
> 208: $db?print qq(Tags file = '$xml'\n):"";

Line 208 could also be written as

if($db){
print qq(Tags file = '$xml'\n);
} else {
"";
}

Here, it should be rather obvious that the else block does nothing.
Maybe line 208 would be better off as

print qq(Tags file = '$xml'\n) if $db;

--
Måns Rullgård
mru@inprovide.com

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