Question

I am trying to set some environment variables in Perl at the very beginning of the program, but I keep receiving errors unless I set them in a Bash script that calls my Perl script.

#!/usr/bin/perl -w
$ENV{'ORACLE_HOME'}='path';
$ENV{'LD_LIBRARY_PATH'}='path';

This does not work, but my shell script does:

#!/bin/bash
export ORACLE_HOME=path
export LD_LIBRARY_PATH=path
./perlscript.pl

I am setting these paths in order to get my DBI module to work. Ideally, I would like to set the paths in the Perl script and not use a Bash script.

Error:

Install_driver (Oracle) failed: Can’t load /some/path/ for module DBD:Oracle: libclntsh.so.11.1: Cannot open shared object file: No such file or directory at /some/path/DynaLoader.pm line 230

Code

use DBI;
my $dbh = DBI->connect("DBI:Oracle:host=something;port=something;sid=something");
my $sth = $dbh->perepare($query);
$sth->execute();
$sth->finish();

Answer 1

IIRC, it’s because the C library makes it own copy of the environment and/or because LD_LIBRARY_PATH is used when the executable is loaded. Workaround:

#!/usr/bin/perl -w
if (!$ENV{ORACLE_HOME}) {
    $ENV{ORACLE_HOME} = 'path';
    $ENV{LD_LIBRARY_PATH} = 'path';
    exec($^X, '--', $0, @ARGV);
}
...

In case I’m wrong, try the following first. It makes sure the environment vars are set before the modules that use them are loaded.

#!/usr/bin/perl -w
BEGIN {
    $ENV{ORACLE_HOME} = 'path';
    $ENV{LD_LIBRARY_PATH} = 'path';
}
...