System

argv

Get command-line parameters. The parameters are numbered starting from 1, the zeroth parameter being the script name.

Type:

(?default : string, int) -> string

Arguments:

• default (of type string, which defaults to "")
• (unlabeled) (of type int)

environment

Return the process environment.

Type:

() -> [string * string]

environment.set

Set the value associated to a variable in the process environment.

Type:

(string, string) -> unit

Arguments:

• (unlabeled) (of type string): Variable to be set.
• (unlabeled) (of type string): Value to set.

exe_ext

Executable file extension.

Type:

string

exit

Immediately stop the application. This should only be used in extreme cases or to specify an exit value. The recommended way of stopping Liquidsoap is to use shutdown.

Type:

(int) -> unit

Arguments:

• (unlabeled) (of type int): Exit value.

getopt

Parse command line options: getopt("-o") returns "1" if "-o" was passed without any parameter, "0" otherwise. getopt(default="X","-o") returns "Y" if "-o Y" was passed, "X" otherwise. The result is removed from the list of arguments, affecting subsequent calls to argv() and getopt().

Type:

(?default : string, string) -> string

Arguments:

• default (of type string, which defaults to "")
• (unlabeled) (of type string)

on_cleanup

Register a function to be called for the final cleanup.

Type:

((() -> unit)) -> unit

Arguments:

• (unlabeled) (of type () -> unit)

on_shutdown

Register a function to be called when Liquidsoap shuts down.

Type:

((() -> unit)) -> unit

Arguments:

• (unlabeled) (of type () -> unit)

on_start

Register a function to be called when Liquidsoap starts.

Type:

((() -> unit)) -> unit

Arguments:

• (unlabeled) (of type () -> unit)

os.type

Type of OS running liquidsoap.

Type:

string

process.pid

Get the process' pid.

Type:

() -> int

process.quote

Return a quoted copy of the given string, suitable for use as one argument in a command line, escaping all meta-characters. Warning: under Windows, the output is only suitable for use with programs that follow the standard Windows quoting conventions.

Type:

(string) -> string

Arguments:

• (unlabeled) (of type string): String to escape

process.quote.command

Return a quoted command line, suitable for use as an argument to process.run.

The optional arguments stdin, stdout and stderr are file names used to redirect the standard input, the standard output, or the standard error of the command.

If stdin=f is given, a redirection < f is performed and the standard input of the command reads from file f.

If stdout=f is given, a redirection > f is performed and the standard output of the command is written to file f.

If stderr=f is given, a redirection 2> f is performed and the standard error of the command is written to file f.

If both stdout=f and stderr=f are given, with the exact same file name f, a 2>&1 redirection is performed so that the standard output and the standard error of the command are interleaved and redirected to the same file f.

Type:

(?stdin : string?, ?stdout : string?, ?stderr : string?, ?args : [string],
 string) -> string

Arguments:

• stdin (of type string?, which defaults to null): command standard input
• stdout (of type string?, which defaults to null): command standard output
• stderr (of type string?, which defaults to null): command standard error
• args (of type [string], which defaults to []): command arguments
• (unlabeled) (of type string): Command to execute

process.run

Run a process in a shell environment. Returns the standard output, as well as standard error and status as methods. The status can be "exit" (the status code is set), "killed" or "stopped" (the status code is the signal), or "exception" (the description is set) or "timeout" (the description is the run time).

Type:

(?env : [string * string], ?inherit_env : bool, ?stdin : string,
 ?rwdirs : [string], ?rodirs : [string], ?network : bool?, ?timeout : float?,
 string) -> unit

Arguments:

• env (of type [string * string], which defaults to []): Process environment
• inherit_env (of type bool, which defaults to true): Inherit calling process's environment when env parameter is empty.
• stdin (of type string, which defaults to ""): Data to write to the process' standard input.
• rwdirs (of type [string], which defaults to ["default"]): Read/write directories for sandboxing. "default" expands to sandbox default.
• rodirs (of type [string], which defaults to ["default"]): Read-only directories for sandboxing "default" expands to sandbox default.
• network (of type bool?, which defaults to null): Enable or disable network inside sandboxed environment (sandbox default if not specified).
• timeout (of type float?, which defaults to null): Cancel process after timeout has elapsed. Ignored if negative.
• (unlabeled) (of type string): Command to run

Methods:

• status (of type string.{code : int, description : string}): Status when process ended, can be one of "exit" (the program exited, the status code is then relevant), "killed" (the program was killed by signal given in status code), "stopped" (the program was stopped by signal given in status code) or "exception" (the program raised and exception detailed in the description).
• stderr (of type string): Messages written by process on standard error stream.
• stdout (of type string): Messages written by process on standard output stream.

process.stderr

The process' stderr

Type:

socket
.{
  close : () -> unit,
  closed : () -> bool,
  non_blocking : (bool) -> unit,
  read : ((?timeout : float?) -> string)
  .{wait : (?timeout : float?, (() -> unit)) -> unit
  },
  type : string,
  write : ((?timeout : float?, string) -> unit)
  .{wait : (?timeout : float?, (() -> unit)) -> unit
  }
}

process.stdin

The process' stdin

Type:

socket
.{
  close : () -> unit,
  closed : () -> bool,
  non_blocking : (bool) -> unit,
  read : ((?timeout : float?) -> string)
  .{wait : (?timeout : float?, (() -> unit)) -> unit
  },
  type : string,
  write : ((?timeout : float?, string) -> unit)
  .{wait : (?timeout : float?, (() -> unit)) -> unit
  }
}

process.stdout

The process' stdout

Type:

socket
.{
  close : () -> unit,
  closed : () -> bool,
  non_blocking : (bool) -> unit,
  read : ((?timeout : float?) -> string)
  .{wait : (?timeout : float?, (() -> unit)) -> unit
  },
  type : string,
  write : ((?timeout : float?, string) -> unit)
  .{wait : (?timeout : float?, (() -> unit)) -> unit
  }
}

process.time

Get the execution time of the current liquidsoap process.

Type:

() -> unit

Methods:

• system (of type float)
• user (of type float)

reopen.stderr

Reopen standard error on the given file

Type:

(string) -> unit

Arguments:

• (unlabeled) (of type string)

reopen.stdin

Reopen standard input on the given file

Type:

(string) -> unit

Arguments:

• (unlabeled) (of type string)

reopen.stdout

Reopen standard output on the given file

Type:

(string) -> unit

Arguments:

• (unlabeled) (of type string)

restart

Restart the application.

Type:

() -> unit

runtime.gc.get

Return the current values of the GC parameters

Type:

() -> unit

Methods:

• allocation_policy (of type int)
• custom_major_ratio (of type int)
• custom_minor_max_size (of type int)
• custom_minor_ratio (of type int)
• major_heap_increment (of type int)
• max_overhead (of type int)
• minor_heap_size (of type int)
• space_overhead (of type int)
• stack_limit (of type int)
• verbose (of type int)
• window_size (of type int)

runtime.gc.print_stat

Print the current values of the memory management counters in human-readable form.

Type:

() -> unit

runtime.gc.quick_stat

Same as stat except that live_words, live_blocks, free_words, free_blocks, largest_free, and fragments are set to 0. This function is much faster than gc.stat because it does not need to go through the heap.

Type:

() -> unit

Methods:

• compactions (of type int)
• forced_major_collections (of type int)
• fragments (of type int)
• free_blocks (of type int)
• free_words (of type int)
• heap_chunks (of type int)
• heap_words (of type int)
• largest_free (of type int)
• live_blocks (of type int)
• live_words (of type int)
• major_collections (of type int)
• major_words (of type float)
• minor_collections (of type int)
• minor_words (of type float)
• promoted_words (of type float)
• stack_size (of type int)
• top_heap_words (of type int)

runtime.gc.set

Set the GC parameters.

Type:

(
 {
   allocation_policy : int,
   custom_major_ratio : int,
   custom_minor_max_size : int,
   custom_minor_ratio : int,
   major_heap_increment : int,
   max_overhead : int,
   minor_heap_size : int,
   space_overhead : int,
   stack_limit : int,
   verbose : int,
   window_size : int
 }) -> unit

Arguments:

• (unlabeled) (of type { allocation_policy : int, custom_major_ratio : int, custom_minor_max_size : int, custom_minor_ratio : int, major_heap_increment : int, max_overhead : int, minor_heap_size : int, space_overhead : int, stack_limit : int, verbose : int, window_size : int })

runtime.gc.stat

Return the current values of the memory management counters. This function examines every heap block to get the statistics.

Type:

() -> unit

Methods:

• compactions (of type int)
• forced_major_collections (of type int)
• fragments (of type int)
• free_blocks (of type int)
• free_words (of type int)
• heap_chunks (of type int)
• heap_words (of type int)
• largest_free (of type int)
• live_blocks (of type int)
• live_words (of type int)
• major_collections (of type int)
• major_words (of type float)
• minor_collections (of type int)
• minor_words (of type float)
• promoted_words (of type float)
• stack_size (of type int)
• top_heap_words (of type int)

runtime.locale.set

Set the system's locale. This sets LANG and LC_ALL environment variables to the given value and then calls setlocale. This is set to "C" on startup, which defaults to the system's default locale. Keep in mind that changing this can potentially impact some functions such a float_of_string.

Type:

(string) -> unit

Arguments:

• (unlabeled) (of type string)

runtime.memory

Returns information about the system and process' memory.

Type:

() -> unit

Methods:

• process_physical_memory (of type int)
• process_private_memory (of type int)
• process_swapped_memory (of type int)
• process_virtual_memory (of type int)
• total_physical_memory (of type int)
• total_used_physical_memory (of type int)
• total_used_virtual_memory (of type int)
• total_virtual_memory (of type int)

runtime.sys.word_size

Size of one word on the machine currently executing the program, in bits. Either 32 or 64.

Type:

int

shutdown

Shutdown the application.

Type:

(?code : int) -> unit

Arguments:

• code (of type int, which defaults to 0): Exit code. Default: 0

source.is_up

Check whether a source is up.

Type:

(source('a)) -> bool

Arguments:

• (unlabeled) (of type source('a))