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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2018-09-10 11:26:34 +0200 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2018-09-10 11:26:34 +0200 |
| commit | f957eebd2d9320564e9fcd13037f3e96fd5d4d34 (patch) | |
| tree | 0000e6a7002c6f887c79f53590b660e12f064710 | |
| parent | 96123f413dfebae7e6441729f93092cd76abe3c4 (diff) | |
| download | man-pages-f957eebd2d9320564e9fcd13037f3e96fd5d4d34.tar.gz | |
clone.2: Clarify the discussion of threads and signals
And explicitly introduce the terms "process-directed" and
"thread-directed" signals.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
| -rw-r--r-- | man2/clone.2 | 40 |
1 files changed, 26 insertions, 14 deletions
diff --git a/man2/clone.2 b/man2/clone.2 index e4fa3a911b..c7874fa59c 100644 --- a/man2/clone.2 +++ b/man2/clone.2 @@ -722,28 +722,40 @@ also requires .BR CLONE_VM to be included). .IP -Signals may be sent to a thread group as a whole (i.e., a TGID) using -.BR kill (2), -or to a specific thread (i.e., TID) using -.BR tgkill (2). -.IP Signal dispositions and actions are process-wide: if an unhandled signal is delivered to a thread, then it will affect (terminate, stop, continue, be ignored in) all members of the thread group. .IP Each thread has its own signal mask, as set by -.BR sigprocmask (2), -but signals can be pending either: for the whole process -(i.e., deliverable to any member of the thread group), -when sent with -.BR kill (2); -or for an individual thread, when sent with -.BR tgkill (2). +.BR sigprocmask (2). +.IP +A signal may be process-directed or thread-directed. +A process-directed signal is targeted at a thread group (i.e., a TGID), +and is delivered to an arbitrarily selected thread from among those +that are not blocking the signal. +A signal may be process directed because it is was generated by the kernel +for reasons other than a hardware exception, or because it was sent using +.BR kill (2) +or +.BR sigqueue (3). +A thread-directed signal is targeted at (i.e., delivered to) +a specific thread. +A signal may be thread directed because it was sent using +.BR tgkill (2) +or +.BR pthread_sigqueue (3), +or because the thread executed a machine language instruction that triggered +a hardware exception +(e.g., invalid memory access triggering +.BR SIGSEGV +or a floating-point exception triggering +.BR SIGFPE ). +.IP A call to .BR sigpending (2) -returns a signal set that is the union of the signals pending for the -whole process and the signals that are pending for the calling thread. +returns a signal set that is the union of the pending process-directed +signals and the signals that are pending for the calling thread. .IP If a process-directed signal is delivered to a thread group, and the thread group has installed a handler for the signal, then |