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.
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
75 replaced 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
118 optional 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 getcwd : unit -> string
136 Return the current working directory of the process.
138 val readdir : string -> string array
142 Return the names of all files present in the given directory. Names
144 denoting the current directory and the parent directory ( "." and ".."
145 in Unix) are not returned. Each string in the result is a file name
146 rather than a complete path. There is no guarantee that the name
147 strings in the resulting array will appear in any specific order; they
148 are not, in particular, guaranteed to appear in alphabetical order.
149 val interactive : bool ref
153 This reference is initially set to false in standalone programs and to
155 true if the code is being executed under the interactive toplevel sys‐
156 tem ocaml .
157 val os_type : string
161 Operating system currently executing the OCaml program. One of
163 - "Unix" (for all Unix versions, including Linux and Mac OS X),
165 - "Win32" (for MS-Windows, OCaml compiled with MSVC++ or Mingw),
167 - "Cygwin" (for MS-Windows, OCaml compiled with Cygwin).
169 type backend_type =
173 | Native
174 | Bytecode
175 | Other of string
176 Currently, the official distribution only supports Native and Bytecode
179 , but it can be other backends with alternative compilers, for example,
180 javascript.
181 Since 4.04.0
184 val backend_type : backend_type
188 Backend type currently executing the OCaml program.
190 Since 4.04.0
193 val unix : bool
197 True if Sys.os_type = "Unix" .
199 Since 4.01.0
202 val win32 : bool
206 True if Sys.os_type = "Win32" .
208 Since 4.01.0
211 val cygwin : bool
215 True if Sys.os_type = "Cygwin" .
217 Since 4.01.0
220 val word_size : int
224 Size of one word on the machine currently executing the OCaml program,
226 in bits: 32 or 64.
227 val int_size : int
231 Size of int , in bits. It is 31 (resp. 63) when using OCaml on a 32-bit
233 (resp. 64-bit) platform. It may differ for other implementations, e.g.
234 it can be 32 bits when compiling to JavaScript.
235 Since 4.03.0
238 val big_endian : bool
242 Whether the machine currently executing the Caml program is big-endian.
244 Since 4.00.0
247 val max_string_length : int
251 Maximum length of strings and byte sequences.
253 val max_array_length : int
257 Maximum length of a normal array (i.e. any array whose elements are not
259 of type float ). The maximum length of a float array is max_floatar‐
260 ray_length if OCaml was configured with --enable-flat-float-array and
261 max_array_length if configured with --disable-flat-float-array .
262 val max_floatarray_length : int
266 Maximum length of a floatarray. This is also the maximum length of a
268 float array when OCaml is configured with --enable-flat-float-array .
269 val runtime_variant : unit -> string
273 Return the name of the runtime variant the program is running on. This
275 is normally the argument given to -runtime-variant at compile time, but
276 for byte-code it can be changed after compilation.
277 Since 4.03.0
280 val runtime_parameters : unit -> string
284 Return the value of the runtime parameters, in the same format as the
286 contents of the OCAMLRUNPARAM environment variable.
287 Since 4.03.0
290 Signal handling
295 type signal_behavior =
296 | Signal_default
297 | Signal_ignore
298 | Signal_handle of (int -> unit)
299 What to do when receiving a signal:
302 - Signal_default : take the default behavior (usually: abort the pro‐
304 gram)
305 - Signal_ignore : ignore the signal
307 - Signal_handle f : call function f , giving it the signal number as
309 argument.
310 val signal : int -> signal_behavior -> signal_behavior
315 Set the behavior of the system on receipt of a given signal. The first
317 argument is the signal number. Return the behavior previously associ‐
318 ated with the signal. If the signal number is invalid (or not available
319 on your system), an Invalid_argument exception is raised.
320 val set_signal : int -> signal_behavior -> unit
324 Same as Sys.signal but return value is ignored.
326 Signal numbers for the standard POSIX signals.
331 val sigabrt : int
332 Abnormal termination
334 val sigalrm : int
338 Timeout
340 val sigfpe : int
344 Arithmetic exception
346 val sighup : int
350 Hangup on controlling terminal
352 val sigill : int
356 Invalid hardware instruction
358 val sigint : int
362 Interactive interrupt (ctrl-C)
364 val sigkill : int
368 Termination (cannot be ignored)
370 val sigpipe : int
374 Broken pipe
376 val sigquit : int
380 Interactive termination
382 val sigsegv : int
386 Invalid memory reference
388 val sigterm : int
392 Termination
394 val sigusr1 : int
398 Application-defined signal 1
400 val sigusr2 : int
404 Application-defined signal 2
406 val sigchld : int
410 Child process terminated
412 val sigcont : int
416 Continue
418 val sigstop : int
422 Stop
424 val sigtstp : int
428 Interactive stop
430 val sigttin : int
434 Terminal read from background process
436 val sigttou : int
440 Terminal write from background process
442 val sigvtalrm : int
446 Timeout in virtual time
448 val sigprof : int
452 Profiling interrupt
454 val sigbus : int
458 Bus error
460 Since 4.03
463 val sigpoll : int
467 Pollable event
469 Since 4.03
472 val sigsys : int
476 Bad argument to routine
478 Since 4.03
481 val sigtrap : int
485 Trace/breakpoint trap
487 Since 4.03
490 val sigurg : int
494 Urgent condition on socket
496 Since 4.03
499 val sigxcpu : int
503 Timeout in cpu time
505 Since 4.03
508 val sigxfsz : int
512 File size limit exceeded
514 Since 4.03
517 exception Break
521 Exception raised on interactive interrupt if Sys.catch_break is on.
524 val catch_break : bool -> unit
528 catch_break governs whether interactive interrupt (ctrl-C) terminates
531 the program or raises the Break exception. Call catch_break true to
532 enable raising Break , and catch_break false to let the system termi‐
533 nate the program on user interrupt.
534 val ocaml_version : string
538 ocaml_version is the version of OCaml. It is a string of the form
541 "major.minor[.patchlevel][(+|~)additional-info]" , where major , minor
542 , and patchlevel are integers, and additional-info is an arbitrary
543 string. The [.patchlevel] part is absent for versions anterior to
544 3.08.0. The [(+|~)additional-info] part may be absent.
545 val enable_runtime_warnings : bool -> unit
549 Control whether the OCaml runtime system can emit warnings on stderr.
551 Currently, the only supported warning is triggered when a channel cre‐
552 ated by open_* functions is finalized without being closed. Runtime
553 warnings are disabled by default.
554 Since 4.03.0
557 val runtime_warnings_enabled : unit -> bool
561 Return whether runtime warnings are currently enabled.
563 Since 4.03.0
566 Optimization
571 val opaque_identity : 'a -> 'a
572 For the purposes of optimization, opaque_identity behaves like an
574 unknown (and thus possibly side-effecting) function.
575 At runtime, opaque_identity disappears altogether.
577 A typical use of this function is to prevent pure computations from
579 being optimized away in benchmarking loops. For example:
580 for _round = 1 to 100_000 do
581 ignore (Sys.opaque_identity (my_pure_computation ()))
582 done
583 Since 4.03.0
587 module Immediate64 : sig end
590OCamldoc 2020-09-01 Sys(3)