siginfo(5) siginfo(5)
NAME
siginfo - signal generation information
SYNOPSIS
#include <siginfo.h>
DESCRIPTION
If a process is catching a signal, it may request information
that tells why the system generated that signal [see
sigaction(2)]. If a process is monitoring its children, it
may receive information that tells why a child changed state
[see waitid(2)]. In either case, the system returns the
information in a structure of type siginfo_t, which includes
the following information:
int si_signo /* signal number */
int si_errno /* error number */
int si_code /* signal code */
si_signo contains the system-generated signal number. (For
the waitid(2) function, si_signo is always SIGCHLD.)
If si_errno is non-zero, it contains an error number
associated with this signal, as defined in errno.h.
si_code contains a code identifying the cause of the signal.
If the value of si_code 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:
pid_t si_pid /* sending process ID */
uid_t si_uid /* sending user ID */
Otherwise, si_code contains a signal-specific reason why the
signal was generated, as follows:
Signal Code Reason
_______________________________________________________________
SIGILL ILL_ILLOPC illegal opcode
ILL_ILLOPN illegal operand
ILL_ILLADR illegal addressing mode
ILL_ILLTRP illegal trap
ILL_PRVOPC privileged opcode
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siginfo(5) siginfo(5)
Signal Code Reason
_______________________________________________________________
ILL_PRVREG privileged register
ILL_COPROC co-processor error
ILL_BADSTK internal stack error
_______________________________________________________________
SIGFPE FPE_INTDIV integer divide by zero
FPE_INTOVF integer overflow
FPE_FLTDIV floating point divide by zero
FPE_FLTOVF floating point overflow
FPE_FLTUND floating point underflow
FPE_FLTRES floating point inexact result
FPE_FLTINV invalid floating point operation
FPE_FLTSUB subscript out of range
SIGSEGV SEGV_MAPERR address not mapped to object
SEGV_ACCERR invalid permissions for mapped object
_______________________________________________________________
SIGBUS BUS_ADRALN invalid address alignment
BUS_ADRERR non-existent physical address
BUS_OBJERR object specific hardware error
_______________________________________________________________
SIGTRAP TRAP_BRKPT process breakpoint
TRAP_TRACE process trace trap
_______________________________________________________________
SIGCHLD CLD_EXITED child has exited
CLD_KILLED child was killed
CLD_DUMPED child terminated abnormally
CLD_TRAPPED traced child has trapped
CLD_STOPPED child has stopped
CLD_CONTINUED stopped child had continued
_______________________________________________________________
SIGPOLL POLL_IN data input available
POLL_OUT output buffers available
POLL_MSG input message available
POLL_ERR I/O error
POLL_PRI high priority input available
POLL_HUP device disconnected
In addition, the following signal-dependent information is
available for kernel-generated signals:
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siginfo(5) siginfo(5)
Signal Field Value
_________________________________________________________________________
SIGILL caddr_t si_addr address of faulting instruction
SIGFPE
_________________________________________________________________________
SIGSEGV caddr_t si_addr address of faulting memory reference
SIGBUS
_________________________________________________________________________
SIGCHLD pid_t si_pid child process ID
int si_status exit value or signal
_________________________________________________________________________
SIGPOLL long si_band band event for POLL_IN, POLL_OUT, or POLL_MSG
REFERENCES
sigaction(2), signal(5), waitid(2)
NOTICES
For SIGCHLD signals, if si_code is equal to CLD_EXITED, then
si_status is equal to the exit value of the process;
otherwise, it is equal to the signal that caused the process
to change state. For some implementations, the exact value of
si_addr may not be available; in that case, si_addr is
guaranteed to be on the same page as the faulting instruction
or memory reference.
Copyright 1994 Novell, Inc. Page 3