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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2007-05-27 21:03:48 +0000 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2007-05-27 21:03:48 +0000 |
| commit | bc0d5df316ed16de594fd03631a1dc4ae7fead57 (patch) | |
| tree | 200ab7ffde40c2de4d144a104fbf44e6bb9dac1b | |
| parent | b8b64c11c767c9ed6bcce170e77e520697349307 (diff) | |
| download | man-pages-bc0d5df316ed16de594fd03631a1dc4ae7fead57.tar.gz | |
Strengthen warning against the use of signal().
Add siginterrupt(3) to SEE ALSO list.
| -rw-r--r-- | man2/signal.2 | 37 |
1 files changed, 20 insertions, 17 deletions
diff --git a/man2/signal.2 b/man2/signal.2 index 56d2db32e5..0f5c5051ce 100644 --- a/man2/signal.2 +++ b/man2/signal.2 @@ -24,8 +24,9 @@ .\" .\" Modified 2004-11-19, mtk: .\" added pointer to sigaction.2 for details of ignoring SIGCHLD +.\" 2007-06-03, mtk: strengthened portability warning. .\" -.TH SIGNAL 2 2000-04-28 "Linux 2.2" "Linux Programmer's Manual" +.TH SIGNAL 2 2007-06-03 "Linux" "Linux Programmer's Manual" .SH NAME signal \- ANSI C signal handling .SH SYNOPSIS @@ -35,6 +36,15 @@ signal \- ANSI C signal handling .sp .BI "sighandler_t signal(int " signum ", sighandler_t " handler ); .SH DESCRIPTION +The behaviour of +.BR signal () +varies across Unix versions, +and has also varied historically across different versions of Linux. +\fBAvoid its use\fP: use +.BR sigaction (2) +instead. +See \fIPortability\fP below. + The .BR signal () system call installs a new signal handler for the signal with number @@ -74,9 +84,8 @@ and .B SIGSTOP cannot be caught or ignored. .SH "RETURN VALUE" -The .BR signal () -function returns the previous value of the signal handler, or +returns the previous value of the signal handler, or .B SIG_ERR on error. .SH "CONFORMING TO" @@ -90,11 +99,10 @@ ignores a .BR SIGILL , or .B SIGSEGV -signal that was not generated by the +signal that was not generated by .BR kill (2) or the -.BR raise (3) -functions. +.BR raise (3). Integer division by zero has undefined result. On some architectures it will generate a .B SIGFPE @@ -142,25 +150,19 @@ instead of then .BR signal () is redefined as -.B __bsd_signal -and signal has the BSD semantics. +.BR __bsd_signal () +and +.BR signal () +has the BSD semantics. This is not recommended. If one on a glibc2 system defines a feature test macro such as .B _XOPEN_SOURCE or uses a separate -.B sysv_signal +.BR sysv_signal (3) function, one obtains classical behaviour. This is not recommended. - -Trying to change the semantics of this call using -defines and includes is not a good idea. -It is better to avoid -.BR signal () -altogether, and use -.BR sigaction (2) -instead. .SH "SEE ALSO" .BR kill (1), .BR alarm (2), @@ -174,6 +176,7 @@ instead. .BR bsd_signal (3), .BR killpg (3), .BR raise (3), +.BR siginterrupt (3), .BR sigsetops (3), .BR sigvec (3), .BR sysv_signal (3), |