ocaml/stdlib/sys.mli

(* Module [Sys]: system interface *)

val argv: string array
        (* The command line arguments given to the process.
           The first element is the command name used to invoke the program.
           The following elements are the arguments given to the program. *)
external file_exists: string -> bool = "sys_file_exists"
        (* Test if a file with the given name exists. *)
external remove: string -> unit = "sys_remove"
        (* Remove the given file name from the file system. *)
external getenv: string -> string = "sys_getenv"
        (* Return the value associated to a variable in the process
           environment. Raise [Not_found] if the variable is unbound. *)
external command: string -> int = "sys_system_command"
        (* Execute the given shell command and return its exit code. *)
external chdir: string -> unit = "sys_chdir"
        (* Change the current working directory of the process. *)

(*** Signal handling *)

type signal_behavior =
    Signal_default
  | Signal_ignore
  | Signal_handle of (int -> unit)
        (* What to do when receiving a signal:
-          [Signal_default]: take the default behavior
-          [Signal_ignore]: ignore the signal
-          [Signal_handle f]: call function [f], giving it the signal
             number as argument. *)

external signal: int -> signal_behavior -> unit = "install_signal_handler"
        (* Set the behavior of the system on receipt of a given signal.
           The first argument is the signal number. *)

val sigabrt: int   (* Abnormal termination *)
val sigalrm: int   (* Timeout *)
val sigfpe: int    (* Arithmetic exception *)
val sighup: int    (* Hangup on controlling terminal *)
val sigill: int    (* Invalid hardware instruction *)
val sigint: int    (* Interactive interrupt (ctrl-C) *)
val sigkill: int   (* Termination (cannot be ignored) *)
val sigpipe: int   (* Broken pipe *)
val sigquit: int   (* Interactive termination *)
val sigsegv: int   (* Invalid memory reference *)
val sigterm: int   (* Termination *)
val sigusr1: int   (* Application-defined signal 1 *)
val sigusr2: int   (* Application-defined signal 2 *)
val sigchld: int   (* Child process terminated *)
val sigcont: int   (* Continue *)
val sigstop: int   (* Stop *)
val sigtstp: int   (* Interactive stop *)
val sigttin: int   (* Terminal read from background process *)
val sigttou: int   (* Terminal write from background process *)
        (* Signal numbers for the standard POSIX signals. *)

exception Break
        (* Exception raised on interactive interrupt if [catch_break]
           is on. *)

val catch_break: bool -> unit
        (* [catch_break] governs whether interactive interrupt (ctrl-C)
           terminates the program or raises the [Break] exception. 
           Call [catch_break true] to enable raising [Break],
           and [catch_break false] to let the system
	   terminate the program on user interrupt. *)