siginfo - Details of signal generation
#include <siginfo.h>
The siginfo structure provides processes with information
on why a signal was generated, or a process that is monitoring
child processes may receive information that specifies
why a child process changed state. See the sigaction(2) and waitid(2) reference pages for more information.
The type siginfo_t contains the following members: Contains
the system generated signal number. Note that for
the waitid function, this field is always SIGCHLD. Contains,
if non-zero, the errno that is associated with the
signal. Specifies a code that determines whether the signal
was generated by a user process, a specific signal, or
by the kernel. When the value of si_code is less than or
equal to zero (0), the signal was generated by a user process
and the siginfo structure contains the following
additional members:
pid_t si_pid /*sending process ID*/ uid_t si_uid
/*sending user ID*/
See the kill(2) and sigsend(2) reference pages for
more information on these fields.
The following table describes the meaning of the
code generated by a signal. The table lists signals
in alphabetical order.
---------------------------------------------------------
Signal Code Definition
---------------------------------------------------------
SIGBUS BUS_ADRALN invalid address alignment
BUS_ADRERR non-existent physical address
BUS_OBJERR object specific hardware
error
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 has continued
CLD_SIGEXITING child is about to exit
because it received a fatal
signal
SIGILL ILL_ILLOPC illegal opcode
ILL_ILLOPN illegal operand
ILL_ILLADR illegal addressing mode
ILL_ILLTRP illegal trap
ILL_PRVOPC privileged opcode
ILL_PRVREG privileged register
ILL_COPROC coprocessor 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
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
SIGSEGV SEGV_MAPERR address not mapped to object
SEGV_ACCERR invalid permissions for
mapped object
SIGTRAP TRAP_BRKPT process breakpoint
TRAP_TRACE process trace trap
---------------------------------------------------------
When a signal is generated by the system, the meaning
of the code is as follows:
------------------------------------------------------------
Signal Field Description
------------------------------------------------------------
SIGILL caddr_t si_addr address of faulting instruction
SIGFPE
SIGSEGV caddr_t si_addr address of faulting memory
SIGBUS reference
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
------------------------------------------------------------
Note, if the signal is SIGCHLD, and the si_code is
equivalent to CLD_EXITED, si_status is equivalent
to the exit value of the process. If si_code is
not equivalent to CLD_EXITED, the si_status field
is equivalent to the signal that caused the process
to change state. In some instances, si_addr may
not be defined, but si_addr will appear on the same
page as the faulting instruction or memory reference.
Functions: kill(2), sigaction(2), sigsend(2), waitid(2)
Files: signal(4)
siginfo(5)
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