Re: [bug-libsigsegv] libsigsegv under LGPL ?

[Bruno Haible]

Hi Daniel,

> All GNU libraries provide significant functionalities ;-) Some are under 
> GPL (readline), some under LGPL (GMP), some under another license 
> (ncurses),... I don't try to understand/justify these choices :-). A 
> library released under LGPL is easier to integrate in gprolog (specially 
> for the core engine of gprolog). Thus my question about LGPL.

My opinion is that libsigsegv better stays GPL, because it has no
serious competition from the LGPL / BSD/MIT camp.

But you are free to ask RMS; keep me in CC when doing this please.

> Suppose 2 threads sharing a buffer (a stack actually) on which a local 
> handler has been installed with libsigsegv. Both access the buffer using 
> locks. When an overflow occurs, is the libsigsegv code thread- safe (the 
> code catching the signal and calling the user handler) ?

Yes, I believe the code that catches the signal and invokes the user handler
is MT-safe.

But the sigsegv_register / sigsegv_dispatch operations are not MT safe:
If one thread is invoking sigsegv_register while another thread invokes
sigsegv_dispatch, bad things can happen.

Bruno