Hello,
indeed, it is somehow confusing, because in terms of evaluating the return code in logical expression, 'false' means the return code was negative and 'true' means it was positve.
Then the core keywords 'true' and 'false' are just aliases to 1 and 0 for use with core parameters, but their meaning is not related to logical evaluation of function's return code.
Someone decided like 20 years ago to have this kind of logical evaluation and it continued to be like that till now.
There was a regression at some point when return 0 was no longer exiting, being fixed at some point. One may notice the behaviour change if run same config before and after.
In general is not good to just return the value from execution of a function, but evaluate to true or false and return explicitly own values. Instead of
return x()
do:
if(x()) {
return 1;
} else {
return -1;
}
Cheers,
Daniel
On 01.05.23 01:10, Patrick Wakano wrote:
Thanks very much for the clarification Daniel! Appreciate it!
However it does seem that some modules have inconsistencies with return values now. So, for instance, the is_ip_rfc918() says it will return true or false (https://kamailio.org/docs/modules/5.6.x/modules/ipops.html#ipops.f.is_ip_rfc1918
- most functions of this module return true or false) and then when used directly with return, it terminates execution. Based on your explanation, it shouldn't return true or false, but likely -1 or 1, which would never be considered 'return 0'
Also, the below code works in version 5.4, but terminates execution in version 5.6, so are you aware of changes in this behaviour in version 5.5 or 5.6 (before the 5.7 changes you mentioned)?
{
return is_ip_rfc1918("$si");
}
if (route(is_src_private)) {
xlog("L_NOTICE", "SRC private\n");
} else {
xlog("L_NOTICE", "SRC public\n");
}
false is 0 and it was actually designed for setting global parameters, not for use as comparison with functions return code or as parameter for return from route blocks. Like:
The grammar of the language defines a coupe of token variants for same purpose:
YES "yes"|"true"|"on"|"enable"
NO "no"|"false"|"off"|"disable"
Where YES is replaced by 1 and NO is replaced by 0:
<INITIAL>{YES} { count(); yylval.intval=1;
yy_number_str=yytext; return NUMBER; }
<INITIAL>{NO} { count(); yylval.intval=0;
yy_number_str=yytext; return NUMBER; }
In the devel version (upcoming 5.7.0), the evaluation of return mode can be controlled by core parameter return_mode, allowing to switch to a more "standard" mode, similar to other scripting languages -- see:
On 28.04.23 08:14, Patrick Wakano wrote:
I'm using Kamailio version 5.6.4 (installed from the repo
rpm.kamailio.org/centos/7) and noticed that every route that uses "return false" is exiting the script, instead of returning.... This was not the case on version 5.4.6 as the same script is running fine.....
So, as an example, this test code doesn't work as expected. In case the source is a public IP, the script doesn't print the "SRC public" it just exits and then of course every other logic meant to be done is not executed....
route[is_src_private]
{
if (is_ip_rfc1918("$si")) {
return true;
}
return false;
#return is_ip_rfc1918("$si"); # this doesn't work too in case the $si is a public IP
}
if (route(is_src_private)) {
xlog("L_NOTICE", "SRC private\n");
} else {
xlog("L_NOTICE", "SRC public\n");
}
If is_src_private is changed to return -1 instead of false, then it all works fine.
Also, I noticed that the following code will print "TEST: 0" in case the $si is public and then stop execution. So looks like false is really being converted to 0, but I guess that's unexpected... anyway apologies if I'm missing something
obvious....
route[is_src_private]
{
$var(t) = false;
if (is_ip_rfc1918("$si")) {
$var(t) = true;
}
xlog("L_ERR", "TEST: $var(t)\n");
return $var(t);
}
I could not find a recent ticket or email related to this situation and I've already spent hours trying to understand what is the logic/problem here, so would anyone have been across a similar case that could provide some insight and clarify
what is the expected behaviour of the false usage (and boolean in general if possible)?
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Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Kamailio World Conference - June 5-7, 2023 - www.kamailioworld.com
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Kamailio World Conference - June 5-7, 2023 - www.kamailioworld.com