OSX 10.3.9 on PowerPC G4: still useable by BOINC?

On which OS?

Standard Signals
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 the last one for mips. A - denotes that a signal is absent on the corresponding architecture.)

First the signals described in the original POSIX.1-1990 standard.

Signal Value Action Comment
-------------------------------------------------------------------------
SIGHUP 1 Term Hangup detected on controlling terminal or death of controlling process
SIGINT 2 Term Interrupt from keyboard
SIGQUIT 3 Core Quit from keyboard
SIGILL 4 Core Illegal Instruction
SIGABRT 6 Core Abort signal from abort(3)
SIGFPE 8 Core Floating point exception
SIGKILL 9 Term Kill signal
SIGSEGV 11 Core Invalid memory reference
SIGPIPE 13 Term Broken pipe: write to pipe with no readers
SIGALRM 14 Term Timer signal from alarm(2)
SIGTERM 15 Term Termination signal
SIGUSR1 30,10,16 Term User-defined signal 1
SIGUSR2 31,12,17 Term User-defined signal 2
SIGCHLD 20,17,18 Ign Child stopped or terminated
SIGCONT 19,18,25 Cont Continue if stopped
SIGSTOP 17,19,23 Stop Stop process
SIGTSTP 18,20,24 Stop Stop typed at tty
SIGTTIN 21,21,26 Stop tty input for background process
SIGTTOU 22,22,27 Stop tty output for background process

The signals SIGKILL and SIGSTOP cannot be caught, blocked, or ignored.

Next the signals not in the POSIX.1-1990 standard but described in SUSv2 and POSIX.1-2001.

Signal Value Action Comment
-------------------------------------------------------------------------
SIGBUS 10,7,10 Core Bus error (bad memory access)
SIGPOLL Term Pollable event (Sys V). Synonym of SIGIO
SIGPROF 27,27,29 Term Profiling timer expired
SIGSYS 12,-,12 Core Bad argument to routine (SVr4)
SIGTRAP 5 Core Trace/breakpoint trap
SIGURG 16,23,21 Ign Urgent condition on socket (4.2BSD)
SIGVTALRM 26,26,28 Term Virtual alarm clock (4.2BSD)
SIGXCPU 24,24,30 Core CPU time limit exceeded (4.2BSD)
SIGXFSZ 25,25,31 Core File size limit exceeded (4.2BSD)

Up to and including Linux 2.2, the default behaviour for SIGSYS, SIGXCPU, SIGXFSZ, and (on architectures other than SPARC and MIPS) SIGBUS was to terminate the process (without a core dump). (On some other Unices the default action for SIGXCPU and SIGXFSZ is to terminate the process without a core dump.) Linux 2.4 conforms to the POSIX.1-2001 requirements for these signals, terminating the process with a core dump.

Next various other signals.

Signal Value Action Comment
--------------------------------------------------------------------
SIGIOT 6 Core IOT trap. A synonym for SIGABRT
SIGEMT 7,-,7 Term
SIGSTKFLT -,16,- Term Stack fault on coprocessor (unused)
SIGIO 23,29,22 Term I/O now possible (4.2BSD)
SIGCLD -,-,18 Ign A synonym for SIGCHLD
SIGPWR 29,30,19 Term Power failure (System V)
SIGINFO 29,-,- A synonym for SIGPWR
SIGLOST -,-,- Term File lock lost
SIGWINCH 28,28,20 Ign Window resize signal (4.3BSD, Sun)
SIGUNUSED -,31,- Term Unused signal (will be SIGSYS)

(Signal 29 is SIGINFO / SIGPWR on an alpha but SIGLOST on a sparc.)

SIGEMT is not specified in POSIX.1-2001, but nevertheless appears on most other Unices, where its default action is typically to terminate the process with a core dump.

SIGPWR (which is not specified in POSIX.1-2001) is typically ignored by default on those other Unices where it appears.

SIGIO (which is not specified in POSIX.1-2001) is ignored by default on several other Unices.