CODEWITHSUNDEEP
clinuxsignals
Petr Skocik
Petr Skocik

Reputation: 60145

What's the 0x4000000 sigaction flag on Linux?

It seems that regardless of how I fill struct sigaction for the set call to the sigaction function, the .sa_flags member gets ORed with 0x4000000, or at least that's how I get it if I later retrieve the dispositon with sigaction(Signum, NULL, &sa).

The manpage for sigaction lists the following ORable values for .sa_flags:

SA_NOCLDSTOP
SA_NOCLDWAIT
SA_NODEFER
SA_ONSTACK
SA_RESETHAND
SA_RESTART
SA_SIGINFO

0x4000000 ANDs to 0 with each of the above. What is 0x4000000?

Upvotes: 2

Views: 638

Answers (1)

alk
alk

Reputation: 70981

Referring my comment, from this man-page we learn:

SA_RESTORER

Not intended for application use. This flag is used by C libraries to indicate that the sa_restorer field contains the address of a "signal trampoline". See sigreturn(2) for more details.

Upvotes: 5

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