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Module Std.Signal

module Signal: Signal
type t 
include Comparable.S
include Hashable.S
include Stringable.S
val equal : t -> t -> bool
val of_system_int : int -> t
of_system_int and to_system_int return and take respectively a signal number corresponding to those in the system's /usr/include/bits/signum.h (or equivalent). It is not guaranteed that these numbers are portable across any given pair of systems -- although some are defined as standard by POSIX.
val to_system_int : t -> int
val of_caml_int : int -> t
of_caml_int constructs a Signal.t given an O'Caml internal signal number. This is only for the use of the Core_unix module.
val to_caml_int : t -> int
val to_string : t -> string
to_string t returns a human-readable name: "sigabrt", "sigalrm", ...
type sys_behavior = [ `Continue | `Dump_core | `Ignore | `Stop | `Terminate ]
The default behaviour of the system if these signals trickle to the top level of a program. See include/linux/kernel.h in the Linux kernel source tree (not the file /usr/include/linux/kernel.h).
val default_sys_behavior : t -> sys_behavior
default_sys_behavior t Query the default system behavior for a signal.
val handle_default : t -> unit
handle_default t is set t `Default.
val ignore : t -> unit
ignore t is set t `Ignore.
type pid_spec = [ `Group of Core_kernel.Std.Pid.t | `My_group | `Pid of Core_kernel.Std.Pid.t ] 
val send : t -> pid_spec -> [ `No_such_process | `Ok ]
send signal pid_spec sends signal to the processes specified by pid_spec.

send_i is like send, except that it silently returns if the specified processes don't exist.

send_exn is like send, except that it raises if the specified processes don't exist.

All of send, send_i, and send_exn raise if you don't have permission to send the signal to the specified processes or if signal is unknown.

val send_i : t -> pid_spec -> unit
val send_exn : t -> pid_spec -> unit
val can_send_to : Core_kernel.Std.Pid.t -> bool
can_send_to pid returns true if pid is running and the current process has permission to send it signals.
type sigprocmask_command = [ `Block | `Set | `Unblock ] 
val sigprocmask : sigprocmask_command -> t list -> t list
sigprocmask cmd sigs changes the set of blocked signals. If cmd is `Set, blocked signals are set to those in the list sigs. If cmd is `Block, the signals in sigs are added to the set of blocked signals. If cmd is `Unblock, the signals in sigs are removed from the set of blocked signals. sigprocmask returns the set of previously blocked signals.
val sigpending : unit -> t list
sigpending () returns the set of blocked signals that are currently pending.
val sigsuspend : t list -> unit
sigsuspend sigs atomically sets the blocked signals to sigs and waits for a non-ignored, non-blocked signal to be delivered. On return, the blocked signals are reset to their initial value.

Specific signals, along with their default behavior and meaning.
val abrt : t
Dump_core Abnormal termination
val alrm : t
Terminate Timeout
val chld : t
Ignore Child process terminated
val cont : t
Continue Continue
val fpe : t
Dump_core Arithmetic exception
val hup : t
Terminate Hangup on controlling terminal
val ill : t
Dump_core Invalid hardware instruction
val int : t
Terminate Interactive interrupt (ctrl-C)
val kill : t
Terminate Termination (cannot be ignored)
val pipe : t
Terminate Broken pipe
val prof : t
Terminate Profiling interrupt
val quit : t
Dump_core Interactive termination
val segv : t
Dump_core Invalid memory reference
val stop : t
Stop Stop
val term : t
Terminate Termination
val tstp : t
Stop Interactive stop
val ttin : t
Stop Terminal read from background process
val ttou : t
Stop Terminal write from background process
val usr1 : t
Terminate Application-defined signal 1
val usr2 : t
Terminate Application-defined signal 2
val vtalrm : t
Terminate Timeout in virtual time
val zero : t
Ignore No-op; can be used to test whether the target process exists and the current process has permission to signal it
module Expert: sig .. end
The Expert module contains functions that novice users should avoid, due to their complexity. 
val t_of_sexp : Sexplib.Sexp.t -> t
val sexp_of_t : t -> Sexplib.Sexp.t
val bin_t : t Core_kernel.Std.Bin_prot.Type_class.t
val bin_read_t : t Core_kernel.Std.Bin_prot.Read.reader
val __bin_read_t__ : (int -> t) Core_kernel.Std.Bin_prot.Read.reader
val bin_reader_t : t Core_kernel.Std.Bin_prot.Type_class.reader
val bin_size_t : t Core_kernel.Std.Bin_prot.Size.sizer
val bin_write_t : t Core_kernel.Std.Bin_prot.Write.writer
val bin_writer_t : t Core_kernel.Std.Bin_prot.Type_class.writer

of_system_int and to_system_int return and take respectively a signal number corresponding to those in the system's /usr/include/bits/signum.h (or equivalent). It is not guaranteed that these numbers are portable across any given pair of systems -- although some are defined as standard by POSIX.

of_caml_int constructs a Signal.t given an O'Caml internal signal number. This is only for the use of the Core_unix module.

to_string t returns a human-readable name: "sigabrt", "sigalrm", ...
val sys_behavior_of_sexp : Sexplib.Sexp.t -> sys_behavior
The default behaviour of the system if these signals trickle to the top level of a program. See include/linux/kernel.h in the Linux kernel source tree (not the file /usr/include/linux/kernel.h).
val __sys_behavior_of_sexp__ : Sexplib.Sexp.t -> sys_behavior
val sexp_of_sys_behavior : sys_behavior -> Sexplib.Sexp.t

default_sys_behavior t Query the default system behavior for a signal.

handle_default t is set t `Default.

ignore t is set t `Ignore.

send signal pid_spec sends signal to the processes specified by pid_spec.

send_i is like send, except that it silently returns if the specified processes don't exist.

send_exn is like send, except that it raises if the specified processes don't exist.

All of send, send_i, and send_exn raise if you don't have permission to send the signal to the specified processes or if signal is unknown.

can_send_to pid returns true if pid is running and the current process has permission to send it signals.

sigprocmask cmd sigs changes the set of blocked signals. If cmd is `Set, blocked signals are set to those in the list sigs. If cmd is `Block, the signals in sigs are added to the set of blocked signals. If cmd is `Unblock, the signals in sigs are removed from the set of blocked signals. sigprocmask returns the set of previously blocked signals.

sigpending () returns the set of blocked signals that are currently pending.

sigsuspend sigs atomically sets the blocked signals to sigs and waits for a non-ignored, non-blocked signal to be delivered. On return, the blocked signals are reset to their initial value.

Specific signals, along with their default behavior and meaning.

Dump_core Abnormal termination

Terminate Timeout

Ignore Child process terminated

Continue Continue

Dump_core Arithmetic exception

Terminate Hangup on controlling terminal

Dump_core Invalid hardware instruction

Terminate Interactive interrupt (ctrl-C)

Terminate Termination (cannot be ignored)

Terminate Broken pipe

Terminate Profiling interrupt

Dump_core Interactive termination

Dump_core Invalid memory reference

Stop Stop

Terminate Termination

Stop Interactive stop

Stop Terminal read from background process

Stop Terminal write from background process

Terminate Application-defined signal 1

Terminate Application-defined signal 2

Terminate Timeout in virtual time

Ignore No-op; can be used to test whether the target process exists and the current process has permission to signal it

The Expert module contains functions that novice users should avoid, due to their complexity.

An OCaml signal handler can run at any time, which introduces all the semantic complexities of multithreading. It is much easier to use Async's signal handling, see Async_unix.Signal, which does not involve multithreading, and runs user code as ordinary Async jobs. Also, beware that there can only be a single OCaml signal handler for any signal, so handling a signal with a Core signal handler will interfere if Async is attempting to handle the same signal.

All signal handler functions are called with Exn.handle_uncaught_and_exit, to prevent the signal handler from raising, because raising from a signal handler could raise to any allocation or GC point in any thread, which would be impossible to reason about.

If you do use Core signal handlers, you should strive to make the signal handler perform a simple idempotent action, like setting a ref.

signal t sets the behavior of the system on receipt of signal t and returns the behavior previously associated with t. If t is not available on your system, signal raises.

set t b is ignore (signal t b)

handle t f is set t (`Handle f).