[fpc-pascal]Understanding signals

md md at realmwireless.com
Wed Nov 1 17:17:40 CET 2000

Does anyone know where the best reference for Signals is?

Inside linux.pp, there are a variety of signals defined that I can hook
using sigaction( )

SIGHUP  - Hangup 
SIGINT  - ???
SIGQUIT - A request to terminate ?
SIGILL  - ???
SIGTRAP - Trap What
SIGABRT  - A request to terminate ?
SIGBUS   - Something with 
SIGFPE   - Floating point error occurred
SIGKILL  - Cannot be trapped by signal handler - process if terminated
SIGSEGV - When memory access violation occurs 
SIGPIPE   - Something about reading from a pipe
SIGALRM   - An alarm time period has elapsed
SIGTERM	  - A request to terminate process?
SIGCHLD   - Raised when child process is terminated
SIGCONT   - Continue from a trapped state (debugger)
SIGSTOP   - Cannot be trapped by signal handler
SIGTTIN   - TTY has some information
SIGTTOU   - TTY output ?
SIGURG    - More Bandwidth available
SIGXCPU   - Cpu Timeslice exhausted
SIGPWR    - When power is shutting down.
What is lacking anywhere on the net is any information about the
conditions that must exist before a given signal
is issued to an application.

In the case of SIGSEGV and SIGFPE, there is no information on how to
produce the core dump information
for debugging purposes as well as internal processing that I want to do
during the handling of the signal.

The signals I am interested are those that relate to problem situations
where the process should
be actively terminating itself as soon as possible.  SIGABRT, SIGTERM,
and SIGQUIT come to mind as signals
that should be considered indications of informing the process to
terminate gracefully and immediately.

Which signal is sent to indicate that REBOOT or SHUTDOWN is imminent or

What function uses SigInfoRec ?  It is in linux.pp, but I cannot find
its use anywhere.

Mark Diener
md at realmwireless.com

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