Re: [SR-Users] how can string "0" be equal to int 0?

On Oct 15, 2010 at 12:29, Juha Heinanen jh@tutpro.com wrote:

i have stored in htable a key_value=0 with key_type=1, i.e., string.

then i have this piece of test code:

if (defined($sht(htable=>$var(carrier_key)::id))) {
    xlog("L_INFO", "$sht(htable=>$var(carrier_key)::id) is defined\n");
} else {
    xlog("L_INFO", "$sht(htable=>$var(carrier_key)::id) is NOT defined\n");
};
$var(carrier_id) = $sht(htable=>$var(carrier_key)::id);
if ($var(carrier_id) == (int)0) {
    xlog("L_INFO", "$sht(htable=>$var(carrier_key)::id) is not found\n");
} else {
    xlog("L_INFO", "$sht(htable=>$var(carrier_key)::id) is found\n");
};

and when the piece is executed, this is printed to syslog:

Oct 15 12:20:33 squeeze /usr/sbin/trunk-proxy[2915]: INFO: 0 is defined Oct 15 12:20:33 squeeze /usr/sbin/trunk-proxy[2915]: INFO: 0 is not found

i understand the first line, because the entry is in the htable, but how is it possible that string "0" is equal to int 0?

Because "==" works only with arguments of the same type, 0 it's autoconverted to "0". The alternative would be to log an error.

Here are the rules for ==: /* if left is string, eval left & right as string and use string diff. * if left is int eval as int using int diff * if left is undef, look at right and convert to right type */

Andrei