diff options
Diffstat (limited to 'man7/signal.7')
| -rw-r--r-- | man7/signal.7 | 49 |
1 files changed, 25 insertions, 24 deletions
diff --git a/man7/signal.7 b/man7/signal.7 index 5f3f0e6232..83a7d1be1f 100644 --- a/man7/signal.7 +++ b/man7/signal.7 @@ -10,7 +10,7 @@ .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one. -.\" +.\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from @@ -18,7 +18,7 @@ .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. -.\" +.\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" @@ -42,9 +42,9 @@ signal \- list of available signals Linux supports both POSIX reliable signals (hereinafter "standard signals") and POSIX real-time signals. .SS "Signal Dispositions" -Each signal has a current +Each signal has a current .IR disposition , -which determines how the process behaves when it is delivered +which determines how the process behaves when it is delivered the signal. The entries in the "Action" column of the tables below specify @@ -65,55 +65,56 @@ A process can change the disposition of a signal using .BR sigaction (2) or (less portably) .BR signal (2). -Using these system calls, a process can elect one of the -following behaviours to occur on delivery of the signal: -perform the default action; ignore the signal; +Using these system calls, a process can elect one of the +following behaviours to occur on delivery of the signal: +perform the default action; ignore the signal; or catch the signal with a -.IR "signal handler" , -a programmer-defined function that is automatically invoked +.IR "signal handler" , +a programmer-defined function that is automatically invoked when the signal is delivered. The signal disposition is a per-process attribute: -in a multithreaded application, the disposition of a +in a multithreaded application, the disposition of a particular signal is the same for all threads. .SS "Signal Mask and Pending Signals" A signal may be .IR blocked , which means that it will not be delivered until it is later unblocked. Between the time when it is generated and when it is delivered -a signal is said to be +a signal is said to be .IR pending . -Each thread in a process has an independent -.IR "signal mask" , +Each thread in a process has an independent +.IR "signal mask" , which indicates the set of signals that the thread is currently blocking. A thread can manipulate its signal mask using .BR pthread_sigmask (3). -In a traditional single-threaded application, +In a traditional single-threaded application, .BR sigprocmask (2) can be used to manipulate the signal mask. A signal may be generated (and thus pending) for a process as a whole (e.g., when sent using -.BR kill (2)) -or for a specific thread (e.g., certain signals, -such as SIGSEGV and SIGFPE, generated as a -consequence of executing a specific machine-language instruction +.BR kill (2)) +or for a specific thread (e.g., certain signals, +such as SIGSEGV and SIGFPE, generated as a +consequence of executing a specific machine-language instruction are thread directed, as are signals targeted at a specific thread using .BR pthread_kill (2)). A process-directed signal may be delivered to any one of the threads that does not currently have the signal blocked. -If more than one of the threads has the signal unblocked, then the +If more than one of the threads has the signal unblocked, then the kernel chooses an arbitrary thread to which to deliver the signal. A thread can obtain the set of signals that it currently has pending using .BR sigpending (2). -This set will consist of the union of the set of pending -process-directed signals and the set of signals pending for +This set will consist of the union of the set of pending +process-directed signals and the set of signals pending for the calling thread. .SS "Standard Signals" -Linux supports the standard signals listed below. Several signal numbers +Linux supports the standard signals listed below. +Several signal numbers are architecture dependent, as indicated in the "Value" column. (Where three values are given, the first one is usually valid for alpha and sparc, the middle one for i386, ppc and sh, and @@ -154,7 +155,7 @@ and .B SIGSTOP cannot be caught, blocked, or ignored. -Next the signals not in the POSIX.1-1990 standard but described in +Next the signals not in the POSIX.1-1990 standard but described in SUSv2 and POSIX.1-2001. .TS l c c l @@ -211,7 +212,7 @@ on a sparc.) .B SIGEMT is not specified in POSIX.1-2001, but nevertheless appears -on most other Unix systems, +on most other Unix systems, where its default action is typically to terminate the process with a core dump. |