I have the following in my script 
#!/usr/bin/perl -w

BEGIN {
  open(STDERR, ">>foo.err") or die "invisible error";
  warn localtime() . ": $0 started " . $/;
}

use strict;
use Foo;

start();                     # start the program

while (1) {
  process();               # the main program logic 
  goto_sleep();          # goto sleep
}

### and then, in Foo.pm #######
sub process {

  # create an IMAP connection
  eval {
    $imap = Mail::IMAPClient->new(  
      Server    => $IMAP,
      User      => $UNAME,
      Password  => $PWD, 
      Uid       => 0, 
      Debug     => $DEBUGGING,
    ) or carp "Cannot connect to $IMAP as $UNAME: $@";
  };

  open  LOG, ">>foo.log";
  print LOG ($@) ? "failed with $@\n" : "connected successfully\n";
  close LOG;
}

[download]

My logic is thusly -- if something is wrong enough for the script to not compile, it will write the reason in foo.err and die rightaway. However, if compilation is successful, then it will try to connect to the IMAP host. If that fails, it will write to foo.log and go to sleep for a specified time, and then wake up and try again.

Except, my logic is wrong. If the connection to the IMAP host fails, the error gets written to foo.err and the script dies. This indicates that the script is checking for the IMAP host connection right at compile time.

What am I doing wrong, and how can I achieve what I want?

What I want is -- after the script starts up successfully, I want it to make the connection to the IMAP host. If successful, do the rest of its stuff, else write a note in the log and go to sleep only to try again later.

Update: Stranger still... if the connection fails, I get an error in foo.err, and yet, I also get "connected successfully" in foo.log. This is most bewildering.

In reply to Understanding compiletime vs. runtime by punkish

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