How to ensure my code never exits directly?

eval{
   require $file;
}

/*subsequent code goes here*/
...

If $file contains an exit statement, the subsequent code 开发者_如何学Cdoesn't have a chance to run.

How to work around so that the subsequent code always get its chance to run when eval is done??

---

It's not possible to abort the exit call. $file should use die instead, which can be trapped by an eval.

As a workaround, you can override the exit builtin globally:

BEGIN {
    *CORE::GLOBAL::exit = sub { die "About to exit" } 
}

---

Have a look at the Safe.pm module. It allows you to restrict which operators can be executed . It was meant for situations where you need to execute untrusted code.

---

Haven't done this, but you might be able to redefine perl's exit function with your own that does a die() of a message your main code is aware of. You would then use CORE::exit(), if I remember, to get a true exit.

Better would be to run the new code in a package other than main:: so you don't corrupt main::s exit.

2011-Aug-06 update: for giggles I tried it:

my $code = qq[print qq(hello exit 99\n); exit 99;];  

{
  package Foo; 
  local $@;
  use vars qw(*exit);   #required
  local *exit = sub { die "TRAPPED EXIT: @_\n"; };  #override local to package Foo;
  print "doing eval\n"; 
  eval $code; 
  print "reason=$@\n";
}

print "done\n";       #prove we did not truly exit
exit 2;               #set specific exit code

And yes, Safe.pm is nice for untrusted code, but if the code is trusted, this is easier.

perl exit.pl; echo $?
doing eval
hello exit 99
reason=TRAPPED EXIT: 99
done
2