1Sys(3) OCaml library Sys(3)
2
6 Sys - System interface.
7
9 Module Sys
10
12 Module Sys
13 : sig end
14 System interface.
17 Every function in this module raises Sys_error with an informative mes‐
19 sage when the underlying system call signal an error.
20 val argv : string array
27 The command line arguments given to the process. The first element is
29 the command name used to invoke the program. The following elements
30 are the command-line arguments given to the program.
31 val executable_name : string
35 The name of the file containing the executable currently running. This
37 name may be absolute or relative to the current directory, depending on
38 the platform and whether the program was compiled to bytecode or a na‐
39 tive executable.
40 val file_exists : string -> bool
44 Test if a file with the given name exists.
46 val is_directory : string -> bool
50 Returns true if the given name refers to a directory, false if it
52 refers to another kind of file.
53 Since 3.10.0
56 Raises Sys_error if no file exists with the given name.
59 val remove : string -> unit
63 Remove the given file name from the file system.
65 val rename : string -> string -> unit
69 Rename a file. rename oldpath newpath renames the file called oldpath
71 , giving it newpath as its new name, moving it between directories if
72 needed. If newpath already exists, its contents will be replaced with
73 those of oldpath . Depending on the operating system, the metadata
74 (permissions, owner, etc) of newpath can either be preserved or be re‐
75 placed by those of oldpath .
76 Since 4.06 concerning the "replace existing file" behavior
79 val getenv : string -> string
83 Return the value associated to a variable in the process environment.
85 Raises Not_found if the variable is unbound.
88 val getenv_opt : string -> string option
92 Return the value associated to a variable in the process environment or
94 None if the variable is unbound.
95 Since 4.05
98 val command : string -> int
102 Execute the given shell command and return its exit code.
104 The argument of Sys.command is generally the name of a command followed
106 by zero, one or several arguments, separated by whitespace. The given
107 argument is interpreted by a shell: either the Windows shell cmd.exe
108 for the Win32 ports of OCaml, or the POSIX shell sh for other ports.
109 It can contain shell builtin commands such as echo , and also special
110 characters such as file redirections > and < , which will be honored by
111 the shell.
112 Conversely, whitespace or special shell characters occurring in command
114 names or in their arguments must be quoted or escaped so that the shell
115 does not interpret them. The quoting rules vary between the POSIX
116 shell and the Windows shell. The Filename.quote_command performs the
117 appropriate quoting given a command name, a list of arguments, and op‐
118 tional file redirections.
119 val time : unit -> float
123 Return the processor time, in seconds, used by the program since the
125 beginning of execution.
126 val chdir : string -> unit
130 Change the current working directory of the process.
132 val mkdir : string -> int -> unit
136 Create a directory with the given permissions.
138 Since 4.12.0
141 val rmdir : string -> unit
145 Remove an empty directory.
147 Since 4.12.0
150 val getcwd : unit -> string
154 Return the current working directory of the process.
156 val readdir : string -> string array
160 Return the names of all files present in the given directory. Names
162 denoting the current directory and the parent directory ( "." and ".."
163 in Unix) are not returned. Each string in the result is a file name
164 rather than a complete path. There is no guarantee that the name
165 strings in the resulting array will appear in any specific order; they
166 are not, in particular, guaranteed to appear in alphabetical order.
167 val interactive : bool ref
171 This reference is initially set to false in standalone programs and to
173 true if the code is being executed under the interactive toplevel sys‐
174 tem ocaml .
175 Alert unsynchronized_access. The interactive status is a mutable
178 global state.
179 val os_type : string
183 Operating system currently executing the OCaml program. One of
185 - "Unix" (for all Unix versions, including Linux and Mac OS X),
187 - "Win32" (for MS-Windows, OCaml compiled with MSVC++ or Mingw),
189 - "Cygwin" (for MS-Windows, OCaml compiled with Cygwin).
191 type backend_type =
195 | Native
196 | Bytecode
197 | Other of string
198 Currently, the official distribution only supports Native and Bytecode
201 , but it can be other backends with alternative compilers, for example,
202 javascript.
203 Since 4.04.0
206 val backend_type : backend_type
210 Backend type currently executing the OCaml program.
212 Since 4.04.0
215 val unix : bool
219 True if Sys.os_type = "Unix" .
221 Since 4.01.0
224 val win32 : bool
228 True if Sys.os_type = "Win32" .
230 Since 4.01.0
233 val cygwin : bool
237 True if Sys.os_type = "Cygwin" .
239 Since 4.01.0
242 val word_size : int
246 Size of one word on the machine currently executing the OCaml program,
248 in bits: 32 or 64.
249 val int_size : int
253 Size of int , in bits. It is 31 (resp. 63) when using OCaml on a 32-bit
255 (resp. 64-bit) platform. It may differ for other implementations, e.g.
256 it can be 32 bits when compiling to JavaScript.
257 Since 4.03.0
260 val big_endian : bool
264 Whether the machine currently executing the Caml program is big-endian.
266 Since 4.00.0
269 val max_string_length : int
273 Maximum length of strings and byte sequences.
275 val max_array_length : int
279 Maximum length of a normal array (i.e. any array whose elements are not
281 of type float ). The maximum length of a float array is max_floatar‐
282 ray_length if OCaml was configured with --enable-flat-float-array and
283 max_array_length if configured with --disable-flat-float-array .
284 val max_floatarray_length : int
288 Maximum length of a floatarray. This is also the maximum length of a
290 float array when OCaml is configured with --enable-flat-float-array .
291 val runtime_variant : unit -> string
295 Return the name of the runtime variant the program is running on. This
297 is normally the argument given to -runtime-variant at compile time, but
298 for byte-code it can be changed after compilation.
299 Since 4.03.0
302 val runtime_parameters : unit -> string
306 Return the value of the runtime parameters, in the same format as the
308 contents of the OCAMLRUNPARAM environment variable.
309 Since 4.03.0
312 Signal handling
317 type signal_behavior =
318 | Signal_default
319 | Signal_ignore
320 | Signal_handle of (int -> unit)
321 What to do when receiving a signal:
324 - Signal_default : take the default behavior (usually: abort the pro‐
326 gram)
327 - Signal_ignore : ignore the signal
329 - Signal_handle f : call function f , giving it the signal number as
331 argument.
332 val signal : int -> signal_behavior -> signal_behavior
337 Set the behavior of the system on receipt of a given signal. The first
339 argument is the signal number. Return the behavior previously associ‐
340 ated with the signal. If the signal number is invalid (or not available
341 on your system), an Invalid_argument exception is raised.
342 val set_signal : int -> signal_behavior -> unit
346 Same as Sys.signal but return value is ignored.
348 Signal numbers for the standard POSIX signals.
353 val sigabrt : int
354 Abnormal termination
356 val sigalrm : int
360 Timeout
362 val sigfpe : int
366 Arithmetic exception
368 val sighup : int
372 Hangup on controlling terminal
374 val sigill : int
378 Invalid hardware instruction
380 val sigint : int
384 Interactive interrupt (ctrl-C)
386 val sigkill : int
390 Termination (cannot be ignored)
392 val sigpipe : int
396 Broken pipe
398 val sigquit : int
402 Interactive termination
404 val sigsegv : int
408 Invalid memory reference
410 val sigterm : int
414 Termination
416 val sigusr1 : int
420 Application-defined signal 1
422 val sigusr2 : int
426 Application-defined signal 2
428 val sigchld : int
432 Child process terminated
434 val sigcont : int
438 Continue
440 val sigstop : int
444 Stop
446 val sigtstp : int
450 Interactive stop
452 val sigttin : int
456 Terminal read from background process
458 val sigttou : int
462 Terminal write from background process
464 val sigvtalrm : int
468 Timeout in virtual time
470 val sigprof : int
474 Profiling interrupt
476 val sigbus : int
480 Bus error
482 Since 4.03
485 val sigpoll : int
489 Pollable event
491 Since 4.03
494 val sigsys : int
498 Bad argument to routine
500 Since 4.03
503 val sigtrap : int
507 Trace/breakpoint trap
509 Since 4.03
512 val sigurg : int
516 Urgent condition on socket
518 Since 4.03
521 val sigxcpu : int
525 Timeout in cpu time
527 Since 4.03
530 val sigxfsz : int
534 File size limit exceeded
536 Since 4.03
539 exception Break
543 Exception raised on interactive interrupt if Sys.catch_break is on.
546 val catch_break : bool -> unit
550 catch_break governs whether interactive interrupt (ctrl-C) terminates
553 the program or raises the Break exception. Call catch_break true to
554 enable raising Break , and catch_break false to let the system termi‐
555 nate the program on user interrupt.
556 val ocaml_version : string
560 ocaml_version is the version of OCaml. It is a string of the form "ma‐
563 jor.minor[.patchlevel][(+|~)additional-info]" , where major , minor ,
564 and patchlevel are integers, and additional-info is an arbitrary
565 string. The [.patchlevel] part was absent before version 3.08.0 and
566 became mandatory from 3.08.0 onwards. The [(+|~)additional-info] part
567 may be absent.
568 val development_version : bool
572 true if this is a development version, false otherwise.
575 Since 4.14.0
578 type extra_prefix =
581 | Plus
582 | Tilde
583 type extra_info = extra_prefix * string
588 Since 4.14
591 type ocaml_release_info = {
594 major : int ;
595 minor : int ;
596 patchlevel : int ;
597 extra : extra_info option ;
598 }
599 Since 4.14
602 val ocaml_release : ocaml_release_info
606 ocaml_release is the version of OCaml.
609 Since 4.14
612 val enable_runtime_warnings : bool -> unit
616 Control whether the OCaml runtime system can emit warnings on stderr.
618 Currently, the only supported warning is triggered when a channel cre‐
619 ated by open_* functions is finalized without being closed. Runtime
620 warnings are disabled by default.
621 Since 4.03.0
624 Alert unsynchronized_access. The status of runtime warnings is a muta‐
627 ble global state.
628 val runtime_warnings_enabled : unit -> bool
632 Return whether runtime warnings are currently enabled.
634 Since 4.03.0
637 Alert unsynchronized_access. The status of runtime warnings is a muta‐
640 ble global state.
641 Optimization
646 val opaque_identity : 'a -> 'a
647 For the purposes of optimization, opaque_identity behaves like an un‐
649 known (and thus possibly side-effecting) function.
650 At runtime, opaque_identity disappears altogether.
652 A typical use of this function is to prevent pure computations from be‐
654 ing optimized away in benchmarking loops. For example:
655 for _round = 1 to 100_000 do
656 ignore (Sys.opaque_identity (my_pure_computation ()))
657 done
658 Since 4.03.0
662 module Immediate64 : sig end
665OCamldoc 2023-07-20 Sys(3)