On Apr 3 14:15, Corinna Vinschen wrote: > On Apr 3 11:27, Petr Skočík wrote: > > Hi. Correct me if I'm wrong but POSIX appears to define > > > > https://pubs.opengroup.org/onlinepubs/7908799/xsh/ucontext.h.html > > > > as, among other things, containing the field: > > > > sigset_t uc_sigmask the set of signals that are blocked when this > > context is active > > > > and it also specifies that the third argument to a .sa_sigaction > > signal handler is a ucontext_t* cast to void*. > > > > So it should follow that doing > > > > void act(int Sig, siginfo_t *Info, void *Uctx) > > { > > ucontext_t *uctx = Uctx; > > sigfillset(&uctx->uc_sigmask); > > } > > > > from a signal handler should alter the signal mask of the thread the > > signal ran on. > > > > This is how Linux and MacOS behave, but not CygWin, as the following > > program shows: > > What you're asking for is really complicated. > > The context given to act is the context at the time the signal function > is called. In Cygwin (lower case w) this is a copy of the context. > > sigfillset() has not the faintest clue where this context comes from, it > just sets the signal mask value without taking any further action. > > There are no provisions to control if the called function changes the > context, other than via setcontext / swapcontext, and I don't see that > POSIX requires anything else. Both functions change the current > thread's sigmask according to the value of uc_sigmask.
Or maybe I'm just dumb. Would it suffice if the thread's signal mask is changed to uc_sigmask when the signal function returns? Corinna -- Corinna Vinschen Cygwin Maintainer
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