How can check whether Perl compilation has already completed?

Question

I have some code the requires the application to be completely loaded and compiled before it should be executed.

Is there a way to check whether my Perl program is still in the compilation stage?

I have something that works, but there must be a better way:

sub check_compile {
  printf("checking\n");
  foreach my $depth (0..10) {
    my ($package, $filename, $line, $subroutine) = caller($depth);
    last unless (defined($package));

    printf("  %s %s %s %s %s\n", $depth, $package, $filename, $line, $subroutine);

    if ($subroutine =~ /::BEGIN$/) {
      printf("in compile\n");
      return 1;
    }

  }

  printf("not in compile\n");
  return 0;
}


BEGIN {
  check_compile();
}

use subpkg;

check_compile();

and subpkg.pm contains:

package subpkg;

use strict;
use warnings;

printf("initing subpkg\n");
main::check_compile();

1; # successfully loaded

Answer 1

I assume your code doesn't make much use of eval - otherwise compilation will be taking place 'mixed in' with execution - but you might review the use of INIT and similar blocks here as a possible way to simplify this.

INIT blocks are run just before the Perl runtime begins execution, in "first in, first out" (FIFO) order.

Answer 2

See $^S in perlvar:

Current state of the interpreter.

    $^S         State
    ---------   -------------------
    undef       Parsing module/eval
    true (1)    Executing an eval
    false (0)   Otherwise

The first state may happen in $SIG{DIE} and $SIG{WARN} handlers.

    BEGIN { print "Compile $^S\n" }
    print "Run-time $^S\n";
    eval { print "Eval $^S\n" };

---

    Compile
    Run time 0
    Eval 1

Answer 3

Untested, but AFAIK should do it:

sub main_run_phase_entered {
    local $@;
    ! eval q!use warnings FATAL => 'all'; CHECK{} 1!
}

Update: nope, fails for me (with 5.10.1) in an END{} block. The CHECK{} doesn't run, but doesn't complain either.