Changing tracers runtime and listening to signals

[mariannasb]

I'm using gst-shark and tracers inside a custom C gstreamer application.

I have it working in the sense that I set environment variables before starting the program and then Im able to get the result either in stdout/stderr or a file with the contents of stdout/stderr.

But what I'm really interested in is being able to modify the tracers runtime (GST_TRACERS="..."), to enable/disable them based on need.
Is that possible?
will calling 'setenv("GST_TRACERS","...", 1)' after 'gst_init()' work?

And instead of having the results in stdout/stderr or a file would it be possible to listen to signals from tracers so that I can forward information to other applications?
Something like 'g_signal_connect (bus, "message::error", G_CALLBACK (cb_message_error), NULL);'?