CODEWITHSUNDEEP
cunixprocesssignals
Orca Ninja
Orca Ninja

Reputation: 833

When would a process raise a signal that causes itself to exit?

The cpp documentation states,

It determines if the child process exited because it raised a signal that caused it to exit

regarding the WIFSIGNALED function. What types of situation would cause the process to do such a thing?

Upvotes: 1

Views: 136

Answers (2)

Jonathan Leffler
Jonathan Leffler

Reputation: 754490

If you use assertions to ensure your program is correct, a failed assert will generate a signal, SIGABRT, that causes the process to terminate. This is a deliberate case of a program signalling itself.

Accidental causes of signals could be said to include (integer) division by zero (SIGFPE, funnily enough), misaligned memory access (SIGBUS; happens if you use an odd address to access a type that must be aligned on an even address boundary — but not all systems are fussy about it), or accessing invalid memory addresses (SIGSEGV).

Upvotes: 2

Jorge Israel Peña
Jorge Israel Peña

Reputation: 38616

There are many signals that can cause this, further, there are a variety of ways a process can exit (i.e. with a core dump, etc.). Check out the man page on signals, specifically the section Standard signals to see a table of signals a process can receive and the default disposition for each of those signals. For a list of possible dispositions, check the Signal dispositions section towards the top.

I don't mean this as an RTFM response. That man page really does show a neat and concise table for the kinds of signals that can exit a process.

For example, there is:

SIGFPE - 8 - Core - Floating point exception

Which is sent to the process if it performs a floating point exception, for example a division by zero. This would cause your process to exit with a core dump.

Upvotes: 1

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