Re: [PATCH 3/4] scoped_ignore_signal: Use sigprocmask+sigtimedwait instead of signal

[Simon Marchi via Gdb-patches <gdb-patches@sourceware.org>]

On 2021-06-15 7:14 a.m., Pedro Alves wrote:
> The problem with using signal(...) to temporarily ignore a signal, is
> that that changes the the signal disposition for the whole process.
> If multiple threads do it at the same time, you have a race.
> 
> Fix this by using sigprocmask + sigtimedwait to implement the ignoring
> instead, if available, which I think probably means everywhere except
> Windows nowadays.  This way, we only change the signal mask for the
> current thread, so there's no race.

I tried to build on macOS today and got:


      CXX    compile/compile.o
    In file included from /Users/smarchi/src/binutils-gdb/gdb/compile/compile.c:46:
    /Users/smarchi/src/binutils-gdb/gdb/../gdbsupport/scoped_ignore_signal.h:69:4: error: use of undeclared identifier 'sigtimedwait'
              sigtimedwait (&set, nullptr, &zero_timeout);
              ^

I didn't have time to dig yet.

Simon