Attach to process without timeout?

[reox]

I have installed mprof 0.58 and wanted to monitor an already running process like this:

$ mprof attach 1234

However, after 36000 probings, it stops. I saw that the help specifies that attached processes will record 1h. There is the -t option to control this, but there seems no way to disable the timeout.
-t 0 exists immediately, -t -1 does not work. Obviously, you can enter a very large number...
Is there anything I overlooked?