siginfo(5) DG/UX 5.4.2 siginfo(5)
NAME
siginfo - signal generation information
SYNOPSIS
#include <signal.h>
or
#include <sys/siginfo.h>
DESCRIPTION
When a process has caught a signal, it may have access to additional
information describing why the system generated the signal. This
information may be passed as an argument to the invoked signal
handler, depending upon the system call that was used to establish
the handler and current software development environment [see sde-
target(1)].
There are two versions of the signal information structure: struct
siginfo (defined in signal.h) and struct siginfot (defined in
sys/signal.h).
If an application is compiled with the software development
environment set to m88kdgux or m88kdguxelf, then the siginfot style
of signal information may be reported to the signal handler. This
information will be reported if sigaction(2) was used to establish
the signal handler and the SASIGINFO bit is set in the signal action
structure at the time the call was made [see sigaction(2)]. In this
case, a pointer to an object of type siginfot will be passed as the
second argument to the invoking signal handler, and also a pointer to
an object of type ucontextt will be sent as the third argument [see
sys/ucontext.h]. The fields of the siginfot structure are discussed
in more detail below.
If, however, an application is compiled with the software development
environment set to m88kbcs, m88kocs or m88kdguxcoff then the first
argument available to the handler will be the caught signal number
and a pointer to an object of type struct siginfo will always be
available as the second argument.
A structure of type siginfo_t is also used by waitid(2) to tell a
process why its child changed state.
A siginfo_t structure includes the following information:
int sisigno /* signal number */
int sierrno /* error number */
int sicode /* signal code */
sisigno contains the system-generated signal number. (For the
waitid(2) function, sisigno is always SIGCHLD.)
If sierrno is non-zero, it contains an error number associated with
this signal, as defined in errno.h.
sicode contains a code identifying the cause of the signal. If the
Licensed material--property of copyright holder(s) 1
siginfo(5) DG/UX 5.4.2 siginfo(5)
value of sicode is less than or equal to 0, then the signal was
generated by a user process [see kill(2) and sigsend(2)] and the
siginfo structure contains the following additional information:
pidt sipid /* sending process ID */
uidt siuid /* sending user ID */
Otherwise, sicode contains a signal-specific reason why the signal
was generated, as follows:
Signal Code Reason
SIGILL ILLILLOPC illegal opcode
ILLILLOPN illegal operation number
ILLILLADR illegal address
ILLILLTRP illegal trap
ILLPRVOPC privileged opcode
ILLPRVREG privileged register
ILLCOPROC
ILLBADSTK bad stack
SIGFPE FPEINTDIV integer divide by zero
FPEINTOVF integer overflow
FPEFLTDIV floating point divide by zero
FPEFLTOVF floating point overflow
FPEFLTUND floating point underflow
FPEFLTRES floating point inexact result
FPEFLTINV invalid floating point operation
FPEFLTSUB subscript out of range
SIGSEGV SEGVMAPERR address not mapped to object
SEGVACCERR invalid permissions for mapped object
SIGBUS BUSADRALN invalid address alignment
BUSADRERR address error
BUSOBJERR object error
SIGTRAP TRAPBRKPT process breakpoint
TRAPTRACE process trace trap
SIGCHLD CLDEXITED child has exited
CLDKILLED child was killed
CLDDUMPED child terminated abnormally
CLDTRAPPED traced child has trapped
CLDSTOPPED child has stopped
CLDCONTINUED stopped child had continued
SIGPOLL POLLIN data input available
POLLOUT output buffers available
POLLMSG input message available
POLLERR I/O error
POLLPRI high priority input available
POLLHUP device disconnected
Licensed material--property of copyright holder(s) 2
siginfo(5) DG/UX 5.4.2 siginfo(5)
In addition, the following signal-dependent information is available
for kernel-generated signals:
Signal Field Value
SIGILL caddrt siaddraddress of faulting instruction
SIGFPE (if exception is precise)
SIGSEGV caddrt siaddraddress of faulting memory reference
SIGBUS
SIGCHLD pidt sipid child process ID
int sistatus exit value or signal
SIGPOLL long siband band event for POLLIN, POLLOUT, or POLLMSG
For additional information about M88000 signals (including details
about hardware exceptions, treatment of concurrent exceptions, and
resumption of execution upon return from a signal handler), obtain
System V Application Binary Interface: Motorola 88000 Processor
Supplement from the 88open Consortium, and see "Signals and
Exceptions" in Chapter 3.
SEE ALSO
sde-target(1), sigaction(2), waitid(2), signal(5).
NOTES
For SIGCHLD signals, if sicode is equal to CLDEXITED, then
sistatus is equal to the exit value of the process; otherwise, it is
equal to the signal that caused the process to change state.
Licensed material--property of copyright holder(s) 3