Question

I need to pass messages to my C program from PHP and I am doing this via message queues.

I have the message queues working and both sides can receive messages.

The problem is on the php side formatting the data. I am trying to send C style string, but php handles strings much differently. How would I convert the php string into a null temrinated C string?

Basically I need ‘config1’ to be the null terminated string.

msg_send($mq_id, $MSG_CHANGECONFIG, 'config1', true, false, $error);

It appears php stores strings like so: \”s:8:\\”config1\000\\”; where \ are just escapes.

Is there any way to do this, or a different way to parse this from the C side in order to convert it to a C string?

Answer 1

You can try with

$nullTerminatedString = sprintf("config1%c", 0);
// or directly using escape sequence
$nullTerminatedString = "config\0";
echo strlen(sprintf("config1%c", 0)); # returns 8, so it should work

Taken from here

serialize
The optional serialize controls how the message is sent.
serialize defaults to TRUE which means that the message is serialized
using the same mechanism as the session module before being sent to
the queue. This allows complex arrays and objects to be sent to other
PHP scripts, or if you are using the WDDX serializer, to any WDDX
compatible client.

So your call should be:

msg_send($mq_id, $MSG_CHANGECONFIG, 'config1', **false**, false, $error);