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
39 native 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. Raise Sys_error if no file exists with
53 the given name.
54 Since 3.10.0
57 val remove : string -> unit
61 Remove the given file name from the file system.
63 val rename : string -> string -> unit
67 Rename a file. rename oldpath newpath renames the file called oldpath
69 , giving it newpath as its new name, moving it between directories if
70 needed. If newpath already exists, its contents will be replaced with
71 those of oldpath . Depending on the operating system, the metadata
72 (permissions, owner, etc) of newpath can either be preserved or be
73 replaced by those of oldpath .
74 Since 4.06 concerning the "replace existing file" behavior
77 val getenv : string -> string
81 Return the value associated to a variable in the process environment.
83 Raise Not_found if the variable is unbound.
84 val getenv_opt : string -> string option
88 Return the value associated to a variable in the process environment or
90 None if the variable is unbound.
91 Since 4.05
94 val command : string -> int
98 Execute the given shell command and return its exit code.
100 The argument of Sys.command is generally the name of a command followed
102 by zero, one or several arguments, separated by whitespace. The given
103 argument is interpreted by a shell: either the Windows shell cmd.exe
104 for the Win32 ports of OCaml, or the POSIX shell sh for other ports.
105 It can contain shell builtin commands such as echo , and also special
106 characters such as file redirections > and < , which will be honored by
107 the shell.
108 Conversely, whitespace or special shell characters occuring in command
110 names or in their arguments must be quoted or escaped so that the shell
111 does not interpret them. The quoting rules vary between the POSIX
112 shell and the Windows shell. The Filename.quote_command performs the
113 appropriate quoting given a command name, a list of arguments, and
114 optional file redirections.
115 val time : unit -> float
119 Return the processor time, in seconds, used by the program since the
121 beginning of execution.
122 val chdir : string -> unit
126 Change the current working directory of the process.
128 val getcwd : unit -> string
132 Return the current working directory of the process.
134 val readdir : string -> string array
138 Return the names of all files present in the given directory. Names
140 denoting the current directory and the parent directory ( "." and ".."
141 in Unix) are not returned. Each string in the result is a file name
142 rather than a complete path. There is no guarantee that the name
143 strings in the resulting array will appear in any specific order; they
144 are not, in particular, guaranteed to appear in alphabetical order.
145 val interactive : bool ref
149 This reference is initially set to false in standalone programs and to
151 true if the code is being executed under the interactive toplevel sys‐
152 tem ocaml .
153 val os_type : string
157 Operating system currently executing the OCaml program. One of
159 - "Unix" (for all Unix versions, including Linux and Mac OS X),
161 - "Win32" (for MS-Windows, OCaml compiled with MSVC++ or Mingw),
163 - "Cygwin" (for MS-Windows, OCaml compiled with Cygwin).
165 type backend_type =
169 | Native
170 | Bytecode
171 | Other of string
172 Currently, the official distribution only supports Native and Bytecode
175 , but it can be other backends with alternative compilers, for example,
176 javascript.
177 Since 4.04.0
180 val backend_type : backend_type
184 Backend type currently executing the OCaml program.
186 Since 4.04.0
189 val unix : bool
193 True if Sys.os_type = "Unix" .
195 Since 4.01.0
198 val win32 : bool
202 True if Sys.os_type = "Win32" .
204 Since 4.01.0
207 val cygwin : bool
211 True if Sys.os_type = "Cygwin" .
213 Since 4.01.0
216 val word_size : int
220 Size of one word on the machine currently executing the OCaml program,
222 in bits: 32 or 64.
223 val int_size : int
227 Size of int , in bits. It is 31 (resp. 63) when using OCaml on a 32-bit
229 (resp. 64-bit) platform. It may differ for other implementations, e.g.
230 it can be 32 bits when compiling to JavaScript.
231 Since 4.03.0
234 val big_endian : bool
238 Whether the machine currently executing the Caml program is big-endian.
240 Since 4.00.0
243 val max_string_length : int
247 Maximum length of strings and byte sequences.
249 val max_array_length : int
253 Maximum length of a normal array (i.e. any array whose elements are not
255 of type float ). The maximum length of a float array is max_floatar‐
256 ray_length if OCaml was configured with --enable-flat-float-array and
257 max_array_length if configured with --disable-flat-float-array .
258 val max_floatarray_length : int
262 Maximum length of a floatarray. This is also the maximum length of a
264 float array when OCaml is configured with --enable-flat-float-array .
265 val runtime_variant : unit -> string
269 Return the name of the runtime variant the program is running on. This
271 is normally the argument given to -runtime-variant at compile time, but
272 for byte-code it can be changed after compilation.
273 Since 4.03.0
276 val runtime_parameters : unit -> string
280 Return the value of the runtime parameters, in the same format as the
282 contents of the OCAMLRUNPARAM environment variable.
283 Since 4.03.0
286 Signal handling
291 type signal_behavior =
292 | Signal_default
293 | Signal_ignore
294 | Signal_handle of (int -> unit)
295 What to do when receiving a signal:
298 - Signal_default : take the default behavior (usually: abort the pro‐
300 gram)
301 - Signal_ignore : ignore the signal
303 - Signal_handle f : call function f , giving it the signal number as
305 argument.
306 val signal : int -> signal_behavior -> signal_behavior
311 Set the behavior of the system on receipt of a given signal. The first
313 argument is the signal number. Return the behavior previously associ‐
314 ated with the signal. If the signal number is invalid (or not available
315 on your system), an Invalid_argument exception is raised.
316 val set_signal : int -> signal_behavior -> unit
320 Same as Sys.signal but return value is ignored.
322 Signal numbers for the standard POSIX signals.
327 val sigabrt : int
328 Abnormal termination
330 val sigalrm : int
334 Timeout
336 val sigfpe : int
340 Arithmetic exception
342 val sighup : int
346 Hangup on controlling terminal
348 val sigill : int
352 Invalid hardware instruction
354 val sigint : int
358 Interactive interrupt (ctrl-C)
360 val sigkill : int
364 Termination (cannot be ignored)
366 val sigpipe : int
370 Broken pipe
372 val sigquit : int
376 Interactive termination
378 val sigsegv : int
382 Invalid memory reference
384 val sigterm : int
388 Termination
390 val sigusr1 : int
394 Application-defined signal 1
396 val sigusr2 : int
400 Application-defined signal 2
402 val sigchld : int
406 Child process terminated
408 val sigcont : int
412 Continue
414 val sigstop : int
418 Stop
420 val sigtstp : int
424 Interactive stop
426 val sigttin : int
430 Terminal read from background process
432 val sigttou : int
436 Terminal write from background process
438 val sigvtalrm : int
442 Timeout in virtual time
444 val sigprof : int
448 Profiling interrupt
450 val sigbus : int
454 Bus error
456 Since 4.03
459 val sigpoll : int
463 Pollable event
465 Since 4.03
468 val sigsys : int
472 Bad argument to routine
474 Since 4.03
477 val sigtrap : int
481 Trace/breakpoint trap
483 Since 4.03
486 val sigurg : int
490 Urgent condition on socket
492 Since 4.03
495 val sigxcpu : int
499 Timeout in cpu time
501 Since 4.03
504 val sigxfsz : int
508 File size limit exceeded
510 Since 4.03
513 exception Break
517 Exception raised on interactive interrupt if Sys.catch_break is on.
520 val catch_break : bool -> unit
524 catch_break governs whether interactive interrupt (ctrl-C) terminates
527 the program or raises the Break exception. Call catch_break true to
528 enable raising Break , and catch_break false to let the system termi‐
529 nate the program on user interrupt.
530 val ocaml_version : string
534 ocaml_version is the version of OCaml. It is a string of the form
537 "major.minor[.patchlevel][+additional-info]" , where major , minor ,
538 and patchlevel are integers, and additional-info is an arbitrary
539 string. The [.patchlevel] and [+additional-info] parts may be absent.
540 val enable_runtime_warnings : bool -> unit
544 Control whether the OCaml runtime system can emit warnings on stderr.
546 Currently, the only supported warning is triggered when a channel cre‐
547 ated by open_* functions is finalized without being closed. Runtime
548 warnings are enabled by default.
549 Since 4.03.0
552 val runtime_warnings_enabled : unit -> bool
556 Return whether runtime warnings are currently enabled.
558 Since 4.03.0
561 Optimization
566 val opaque_identity : 'a -> 'a
567 For the purposes of optimization, opaque_identity behaves like an
569 unknown (and thus possibly side-effecting) function.
570 At runtime, opaque_identity disappears altogether.
572 A typical use of this function is to prevent pure computations from
574 being optimized away in benchmarking loops. For example:
575 for _round = 1 to 100_000 do
576 ignore (Sys.opaque_identity (my_pure_computation ()))
577 done
578 Since 4.03.0
582 module Immediate64 : sig end
585OCamldoc 2020-02-27 Sys(3)