Exception capture and honest success signals

The idea

Block eval catches an exception raised by die and lets a caller inspect failure. Its return value alone can be misleading if successful work legitimately returns zero, an empty string, or undef. Use an explicit final true value inside the protected block as a success sentinel, while storing the operation’s actual result separately.

After failure, capture $@ before other operations that might disturb it. Keep the protected work narrow and choose a recovery policy that does not erase useful context. String eval compiles and executes source text and is a different tool; it should not be used merely to parse ordinary external data. Prefer structured parsing and explicit validation rather than promoting data into executable code.

use strict; use warnings;
my $value;
my $ok=eval { $value=0; 1 };
if (!$ok) { my $error=$@; die $error; }
print "success:$value\n";

success:0

The final one indicates normal completion, while the legitimate zero result remains separate from the success flag.