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sigaction.2: Minor clean-ups to Peter Collingbourne's patch 

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2021-08-09 02:26:50 +02:00
parent 4e7bd2d06b
commit 1875f17753
1 changed files with 7 additions and 7 deletions
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14
man2/sigaction.2
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@ -266,13 +266,13 @@ This flag is meaningful only when establishing a signal handler.
Used to dynamically probe for flag bit support. Used to dynamically probe for flag bit support.
.IP .IP
If an attempt to register a handler succeeds with this flag set in If an attempt to register a handler succeeds with this flag set in
.I act->sa_flags .I act\->sa_flags
alongside other flags that are potentially unsupported by the kernel, alongside other flags that are potentially unsupported by the kernel,
and an immediately subsequent and an immediately subsequent
.BR sigaction () .BR sigaction ()
call specifying the same signal number n and with non-NULL call specifying the same signal number and with a non-NULL
.I oldact .I oldact
yields argument yields
.B SA_UNSUPPORTED .B SA_UNSUPPORTED
.I clear .I clear
in in
@ -888,16 +888,16 @@ filter rule.
The The
.BR sigaction () .BR sigaction ()
call on Linux accepts unknown bits set in call on Linux accepts unknown bits set in
.I act->sa_flags .I act\->sa_flags
without error. without error.
The behavior of the kernel starting with Linux 5.11 is that a second The behavior of the kernel starting with Linux 5.11 is that a second
.BR sigaction () .BR sigaction ()
will clear unknown bits from will clear unknown bits from
.IR oldact->sa_flags . .IR oldact\->sa_flags .
However, historically, a second However, historically, a second
.BR sigaction () .BR sigaction ()
call would typically leave those bits set in call would typically leave those bits set in
.IR oldact->sa_flags . .IR oldact\->sa_flags .
.PP .PP
This means that support for new flags cannot be detected This means that support for new flags cannot be detected
simply by testing for a flag in simply by testing for a flag in
@ -919,7 +919,7 @@ in the signal handler itself.
In kernels that do not support a specific flag, In kernels that do not support a specific flag,
the kernel's behavior is as if the flag was not set, the kernel's behavior is as if the flag was not set,
even if the flag was set in even if the flag was set in
.IR act->sa_flags . .IR act\->sa_flags .
.PP .PP
The flags The flags
.BR SA_NOCLDSTOP , .BR SA_NOCLDSTOP ,