protocol

osp

Portable operating-system access protocol.

Availability:
logtalk_load(os(loader))
Author: Paulo Moura
Version: 1:38:1
Date: 2024-03-25
Compilation flags:
static
Dependencies:
(none)
Remarks:

  • Error handling: Predicates that require a file or directory to exist throw an error when that is not the case. But the exact exception term is currently backend Prolog compiler dependent.

Inherited public predicates:
(none)

Public predicates

pid/1

Returns the process identifier of the running process.

Compilation flags:
static
Template:
pid(PID)
Mode and number of proofs:
pid(-integer) - one

shell/2

Runs an operating-system shell command and returns its exit status.

Compilation flags:
static
Template:
shell(Command,Status)
Mode and number of proofs:
shell(+atom,-integer) - one

shell/1

Runs an operating-system shell command.

Compilation flags:
static
Template:
shell(Command)
Mode and number of proofs:
shell(+atom) - zero_or_one

is_absolute_file_name/1

True iff the argument is an absolute file path. On POSIX systems, this predicate is true if File starts with a /. On Windows systems, this predicate is true if File starts with a drive letter. No attempt is made to expand File as a path.

Compilation flags:
static
Template:
is_absolute_file_name(File)
Mode and number of proofs:
is_absolute_file_name(+atom) - zero_or_one

absolute_file_name/2

Expands a file name to an absolute file path. An environment variable at the beginning of the file name is also expanded.

Compilation flags:
static
Template:
absolute_file_name(File,Path)
Mode and number of proofs:
absolute_file_name(+atom,-atom) - one

decompose_file_name/3

Decomposes a file name into its directory (which always ends with a slash; ./ is returned if absent) and its basename (which can be the empty atom).

Compilation flags:
static
Template:
decompose_file_name(File,Directory,Basename)
Mode and number of proofs:
decompose_file_name(+atom,?atom,?atom) - one

decompose_file_name/4

Decomposes a file name into its directory (which always ends with a slash; ./ is returned if absent), name (that can be the empty atom), and extension (which starts with a . when defined; the empty atom otherwise).

Compilation flags:
static
Template:
decompose_file_name(File,Directory,Name,Extension)
Mode and number of proofs:
decompose_file_name(+atom,?atom,?atom,?atom) - one

path_concat/3

Concatenates a path prefix and a path suffix, adding a / separator if required. Returns Suffix when it is an absolute path. Returns Prefix with a trailing / appended if missing when Suffix is the empty atom.

Compilation flags:
static
Template:
path_concat(Prefix,Suffix,Path)
Mode and number of proofs:
path_concat(+atom,+atom,--atom) - one

internal_os_path/2

Converts between the internal path representation (which is backend dependent) and the operating-system native path representation.

Compilation flags:
static
Template:
internal_os_path(InternalPath,OSPath)
Mode and number of proofs:
internal_os_path(+atom,-atom) - one
internal_os_path(-atom,+atom) - one

make_directory/1

Makes a new directory. Succeeds if the directory already exists.

Compilation flags:
static
Template:
make_directory(Directory)
Mode and number of proofs:
make_directory(+atom) - one

make_directory_path/1

Makes a new directory creating all the intermediate directories if necessary. Succeeds if the directory already exists.

Compilation flags:
static
Template:
make_directory_path(Directory)
Mode and number of proofs:
make_directory_path(+atom) - one

delete_directory/1

Deletes an empty directory. Throws an error if the directory does not exist.

Compilation flags:
static
Template:
delete_directory(Directory)
Mode and number of proofs:
delete_directory(+atom) - one_or_error

change_directory/1

Changes current working directory. Throws an error if the directory does not exist.

Compilation flags:
static
Template:
change_directory(Directory)
Mode and number of proofs:
change_directory(+atom) - one_or_error

working_directory/1

Current working directory.

Compilation flags:
static
Template:
working_directory(Directory)
Mode and number of proofs:
working_directory(?atom) - zero_or_one

temporary_directory/1

Temporary directory. Tries first environment variables: TEMP and TMP on Windows systems; TMPDIR, TMP, TEMP, and TEMPDIR on POSIX systems. When not defined, tries default locations. Returns the working directory as last resort.

Compilation flags:
static
Template:
temporary_directory(Directory)
Mode and number of proofs:
temporary_directory(?atom) - one

null_device_path/1

Null device path: nul on Windows systems and /dev/null on POSIX systems.

Compilation flags:
static
Template:
null_device_path(Path)
Mode and number of proofs:
null_device_path(?atom) - one

full_device_path/1

Full device path: /dev/full on Linux and BSD systems. Fails on other systems. Experimental.

Compilation flags:
static
Template:
full_device_path(Path)
Mode and number of proofs:
full_device_path(?atom) - zero_or_one

read_only_device_path/1

Read-only device path: /dev/urandom on macOS. Fails on other systems. Experimental.

Compilation flags:
static
Template:
read_only_device_path(Path)
Mode and number of proofs:
read_only_device_path(?atom) - zero_or_one

directory_files/2

Returns a list of all files (including directories, regular files, and hidden directories and files) in a directory. File paths are relative to the directory. Throws an error if the directory does not exist.

Compilation flags:
static
Template:
directory_files(Directory,Files)
Mode and number of proofs:
directory_files(+atom,-list(atom)) - one_or_error

directory_files/3

Returns a list of files filtered using the given list of options. Invalid options are ignored. Default option values are equivalent to directory_files/2. Throws an error if the directory does not exist.

Compilation flags:
static
Template:
directory_files(Directory,Files,Options)
Mode and number of proofs:
directory_files(+atom,-list(atom),+list(compound)) - one_or_error
Remarks:

  • Option paths/1: Possible values are relative and absolute. Default is relative.

  • Option type/1: Possible values are all, regular, directory. Default is all.

  • Option extensions/1: Argument is a list of required extensions (using the format '.ext'). Default is the empty list.

  • Option prefixes/1: Argument is a list of required file prefixes (atoms). Default is the empty list.

  • Option suffixes/1: Argument is a list of required file suffixes (atoms). Default is the empty list.

  • Option dot_files/1: Possible values are true and false. Default is true.

directory_exists/1

True if the specified directory exists (irrespective of directory permissions).

Compilation flags:
static
Template:
directory_exists(Directory)
Mode and number of proofs:
directory_exists(+atom) - zero_or_one

ensure_directory/1

Ensures that a directory exists, creating it if necessary.

Compilation flags:
static
Template:
ensure_directory(Directory)
Mode and number of proofs:
ensure_directory(+atom) - one

file_exists/1

True if the specified file exists and is a regular file (irrespective of file permissions).

Compilation flags:
static
Template:
file_exists(File)
Mode and number of proofs:
file_exists(+atom) - zero_or_one

file_modification_time/2

File modification time (which can be used for comparison). Throws an error if the file does not exist.

Compilation flags:
static
Template:
file_modification_time(File,Time)
Mode and number of proofs:
file_modification_time(+atom,-integer) - one_or_error

file_size/2

File size (in bytes). Throws an error if the file does not exist.

Compilation flags:
static
Template:
file_size(File,Size)
Mode and number of proofs:
file_size(+atom,-integer) - one_or_error

file_permission/2

True iff the specified file has the specified permission (read, write, or execute). Throws an error if the file does not exist.

Compilation flags:
static
Template:
file_permission(File,Permission)
Mode and number of proofs:
file_permission(+atom,+atom) - zero_or_one_or_error

copy_file/2

Copies a file. Throws an error if the original file does not exist or if the copy cannot be created.

Compilation flags:
static
Template:
copy_file(File,Copy)
Mode and number of proofs:
copy_file(+atom,+atom) - one_or_error

rename_file/2

Renames a file or a directory. Throws an error if the file or directory does not exist.

Compilation flags:
static
Template:
rename_file(Old,New)
Mode and number of proofs:
rename_file(+atom,+atom) - one_or_error

delete_file/1

Deletes a file. Throws an error if the file does not exist.

Compilation flags:
static
Template:
delete_file(File)
Mode and number of proofs:
delete_file(+atom) - one_or_error

ensure_file/1

Ensures that a file exists, creating it if necessary.

Compilation flags:
static
Template:
ensure_file(File)
Mode and number of proofs:
ensure_file(+atom) - one

environment_variable/2

Returns an environment variable value. Fails if the variable does not exists.

Compilation flags:
static
Template:
environment_variable(Variable,Value)
Mode and number of proofs:
environment_variable(+atom,?atom) - zero_or_one

time_stamp/1

Returns a system-dependent time stamp, which can be used for sorting, but should be regarded otherwise as an opaque term.

Compilation flags:
static
Template:
time_stamp(Time)
Mode and number of proofs:
time_stamp(-ground) - one

date_time/7

Returns the current date and time. Note that most backends do not provide sub-second accuracy and in those cases the value of the Milliseconds argument is always zero.

Compilation flags:
static
Template:
date_time(Year,Month,Day,Hours,Minutes,Seconds,Milliseconds)
Mode and number of proofs:
date_time(-integer,-integer,-integer,-integer,-integer,-integer,-integer) - one

cpu_time/1

System cpu time in seconds.

Compilation flags:
static
Template:
cpu_time(Seconds)
Mode and number of proofs:
cpu_time(-number) - one

wall_time/1

Wall time in seconds.

Compilation flags:
static
Template:
wall_time(Seconds)
Mode and number of proofs:
wall_time(-number) - one

operating_system_type/1

Operating system type. Possible values are unix, windows, and unknown.

Compilation flags:
static
Template:
operating_system_type(Type)
Mode and number of proofs:
operating_system_type(?atom) - zero_or_one

operating_system_name/1

Operating system name. On POSIX systems, it returns the value of uname -s. On Windows systems, it returns 'Windows'.

Compilation flags:
static
Template:
operating_system_name(Name)
Mode and number of proofs:
operating_system_name(?atom) - zero_or_one

operating_system_machine/1

Operating system hardware platform. On POSIX systems, it returns the value of uname -m. On Windows systems, it returns the value of the PROCESSOR_ARCHITECTURE environment variable.

Compilation flags:
static
Template:
operating_system_machine(Machine)
Mode and number of proofs:
operating_system_machine(?atom) - zero_or_one

operating_system_release/1

Operating system release. On POSIX systems, it returns the value of uname -r. On Windows systems, it uses WMI code.

Compilation flags:
static
Template:
operating_system_release(Release)
Mode and number of proofs:
operating_system_release(?atom) - zero_or_one

command_line_arguments/1

Returns a list with the command line arguments that occur after --.

Compilation flags:
static
Template:
command_line_arguments(Arguments)
Mode and number of proofs:
command_line_arguments(-list(atom)) - one

sleep/1

Suspends execution the given number of seconds.

Compilation flags:
static
Template:
sleep(Seconds)
Mode and number of proofs:
sleep(+number) - one

Protected predicates

(none)

Private predicates

(none)

Operators

(none)

See also

os, os_types