Is there any modern alternative to pstack?

[Yuri]

I look at seemingly abandoned sysutils/pstack, last modified upstream 
2002-11-27.
It doesn't really work on 9.0 i386, prints some errors.

It's functions, though, is quite desirable if one wants to understand 
why some multithreaded program hangs or is not responsive.
Since there were no updates, I wonder, is this because there is some 
alternative in FreeBSD that I don't know about, or it is primarily due 
to the lack of interest/resources?

I don't take gdb as alternative since it is not single line, and also it 
has some threading issues of its own.

Yuri