longjump && re-entrancy

I understand (which is to say I believe it is the case)
that it is safe to call longjump() from a signal handler.
I also understand that non-reentrant functions are unsafe
to call from a signal handler. But it seems to me that
if the program ever calls a non-rentrant function and
longjumps out of a signal handler, then all the issues of
non-reentrancy apply. eg:

setjumpbuf
fprintf() <-- interrupted
[in handler]:
longjump

Could hang if printf still has a lock on the FILE *.

Or does the stack unwinding from longjump magically
release the locks?
.

Relevant Pages

  • Re: longjmp vs goto
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  • Re: Catching SIGSEGV with signal() in 2.6
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