siginfo(5) MISC. FILE FORMATS siginfo(5)
NAME
siginfo - signal generation information
SYNOPSIS
#include <siginfo.h>
DESCRIPTION
If a process is catching a signal, it may request informa-
tion 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 siginfot, which 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 associ-
ated with this signal, as defined in errno.h.
sicode contains a code identifying the cause of the signal.
If the value of sicode is less than or equal to 0, then the
signal was generated by a user process [see kill(2) and sig-
send(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 operand
ILLILLADR illegal addressing mode
ILLILLTRP illegal trap
ILLPRVOPC privileged opcode
ILLPRVREG privileged register
ILLCOPROC coprocessor error
ILLBADSTK internal stack error
_______________________________________________________________
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
1
siginfo(5) MISC. FILE FORMATS siginfo(5)
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 non-existent physical address
BUSOBJERR object specific hardware 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
In addition, the following signal-dependent information is
available for kernel-generated signals:
Signal Field Value
________________________________________________________________
SIGILL caddrt siaddr address of faulting instruction
SIGFPE
________________________________________________________________
SIGSEGV caddrt siaddr address 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
NOTES
For SIGCHLD signals, if sicode is equal to CLDEXITED, then
sistatus is equal to the exit value of the process; other-
wise, it is equal to the signal that caused the process to
change state. For some implementations, the exact value of
siaddr may not be available; in that case, siaddr is
guaranteed to be on the same page as the faulting instruc-
tion or memory reference.
2
siginfo(5) MISC. FILE FORMATS siginfo(5)
SEE ALSO
sigaction(2), waitid(2), signal(5).
3