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- # What should happen if non-interactive shell gets SIGINT?
- (sleep 1; echo Sending SIGINT to main shell PID; exec kill -INT $$) &
- # We create a child which exits with 0 even on SIGINT
- # (The complex command is necessary only if SIGINT is generated by ^C,
- # in this testcase even bare "sleep 2" would do because
- # in the testcase we don't send SIGINT *to the child*...)
- $THIS_SH -c 'trap "exit 0" SIGINT; sleep 2'
- # In one second, we (main shell) get SIGINT here.
- # The question is whether we should, or should not, exit.
- # bash will not stop here. It will execute next command(s).
- # The rationale for this is described here:
- # http://www.cons.org/cracauer/sigint.html
- #
- # Basically, bash will not exit on SIGINT immediately if it waits
- # for a child. It will wait for the child to exit.
- # If child exits NOT by dying on SIGINT, then bash will not exit.
- #
- # The idea is that the following script:
- # | emacs file.txt
- # | more cmds
- # User may use ^C to interrupt editor's ops like search. But then
- # emacs exits normally. User expects that script doesn't stop.
- #
- # This is a nice idea, but detecting "did process really exit
- # with SIGINT?" is racy. Consider:
- # | bash -c 'while true; do /bin/true; done'
- # When ^C is pressed while bash waits for /bin/true to exit,
- # it may happen that /bin/true exits with exitcode 0 before
- # ^C is delivered to it as SIGINT. bash will see SIGINT, then
- # it will see that child exited with 0, and bash will NOT EXIT.
- # Therefore we do not implement bash behavior.
- # I'd say that emacs need to put itself into a separate pgrp
- # to isolate shell from getting stray SIGINTs from ^C.
- echo Next command after SIGINT was executed
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