CODEWITHSUNDEEP
unixoperating-systemsignals
KAGDGAP
KAGDGAP

Reputation: 41

What happens inside machine when i send a signal

I mean, i have a request for an operating system, like kill SIG_NUMBER PID, what happens next. What are the actions taken by operating system and so on.

Thanks much

Upvotes: 0

Views: 67

Answers (1)

David Victor
David Victor

Reputation: 827

Depends on the OS of course - but generally assuming you have sufficient privileges to deliver that signal to the process concerned - then the OS will alter the process state for the proc. concerned within the kernel. That will generally result in some "life cycle" state change for the process - i.e. to be terminated, terminating, dead, to be suspended .. etc.

The actual call into the kernel (depending on OS) will be via a system call or maybe an 'ioctl' call via some appropriate device.

When it's the process's turn for some cpu time the proc scheduler will take process state into account to determine what to do next. Deliberately brief here as its quite involved.

I'd suggest looking at some sample source - look at a Linux distro or OpenSolaris maybe (although that's quite complicated).

Example here - warning this is very complicated. OpenSolaris signal handling in the kernel

Upvotes: 1

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