Printing all opened files

[Jean-Eric Cuendet]

> But it is recommended to reuse the systemtap tapset to avoid writing
> your code from the scratch, e.g.
> probe syscall.open
> {
>     printf("%s\n", filename)
> }

Thanks, works well!
I'd like to print also the gettimeofday (or equivalent)
How do I do? Can I call standard methods? Like:

probe syscall.open
{
     printf("STAP OPEN (%d) : %s\n", gettimeofday(), filename)
}