Results for: "partition"

Returns the cube root of x.

• Domain: [-INFINITY, INFINITY].

• Range: [-INFINITY, INFINITY].

Examples:

cbrt(-INFINITY) # => -Infinity
cbrt(-27.0)     # => -3.0
cbrt(-8.0)      # => -2.0
cbrt(-2.0)      # => -1.2599210498948732
cbrt(1.0)       # => 1.0
cbrt(0.0)       # => 0.0
cbrt(1.0)       # => 1.0
cbrt(2.0)       # => 1.2599210498948732
cbrt(8.0)       # => 2.0
cbrt(27.0)      # => 3.0
cbrt(INFINITY)  # => Infinity

Creates a new child process by doing one of the following in that process:

• Passing string command_line to the shell.

• Invoking the executable at exe_path.

This method has potential security vulnerabilities if called with untrusted input; see Command Injection.

Returns the process ID (pid) of the new process, without waiting for it to complete.

To avoid zombie processes, the parent process should call either:

• Process.wait, to collect the termination statuses of its children.

• Process.detach, to register disinterest in their status.

The new process is created using the exec system call; it may inherit some of its environment from the calling program (possibly including open file descriptors).

Argument env, if given, is a hash that affects ENV for the new process; see Execution Environment.

Argument options is a hash of options for the new process; see Execution Options.

The first required argument is one of the following:

• command_line if it is a string, and if it begins with a shell reserved word or special built-in, or if it contains one or more meta characters.

• exe_path otherwise.

Argument command_line

String argument command_line is a command line to be passed to a shell; it must begin with a shell reserved word, begin with a special built-in, or contain meta characters:

spawn('if true; then echo "Foo"; fi') # => 798847 # Shell reserved word.
Process.wait                          # => 798847
spawn('echo')                         # => 798848 # Built-in.
Process.wait                          # => 798848
spawn('date > /tmp/date.tmp')         # => 798879 # Contains meta character.
Process.wait                          # => 798849
spawn('date > /nop/date.tmp')         # => 798882 # Issues error message.
Process.wait                          # => 798882

The command line may also contain arguments and options for the command:

spawn('echo "Foo"') # => 799031
Process.wait        # => 799031

Output:

Foo

See Execution Shell for details about the shell.

Raises an exception if the new process could not execute.

Argument exe_path

Argument exe_path is one of the following:

• The string path to an executable to be called:

  spawn('/usr/bin/date') # Path to date on Unix-style system.
  Process.wait
  

  Output:

  Thu Aug 31 10:06:48 AM CDT 2023

• A 2-element array containing the path to an executable and the string to be used as the name of the executing process:

  pid = spawn(['sleep', 'Hello!'], '1') # 2-element array.
  p `ps -p #{pid} -o command=`
  

  Output:

  "Hello! 1\n"
  

Ruby invokes the executable directly, with no shell and no shell expansion.

If one or more args is given, each is an argument or option to be passed to the executable:

spawn('echo', 'C*')             # => 799392
Process.wait                    # => 799392
spawn('echo', 'hello', 'world') # => 799393
Process.wait                    # => 799393

Output:

C*
hello world

Raises an exception if the new process could not execute.

Exits the process immediately; no exit handlers are called. Returns exit status status to the underlying operating system.

Process.exit!(true)

Values true and false for argument status indicate, respectively, success and failure; The meanings of integer values are system-dependent.

Initiates termination of the Ruby script by raising SystemExit; the exception may be caught. Returns exit status status to the underlying operating system.

Values true and false for argument status indicate, respectively, success and failure; The meanings of integer values are system-dependent.

Example:

begin
  exit
  puts 'Never get here.'
rescue SystemExit
  puts 'Rescued a SystemExit exception.'
end
puts 'After begin block.'

Output:

Rescued a SystemExit exception.
After begin block.

Just prior to final termination, Ruby executes any at-exit procedures (see Kernel::at_exit) and any object finalizers (see ObjectSpace::define_finalizer).

Example:

at_exit { puts 'In at_exit function.' }
ObjectSpace.define_finalizer('string', proc { puts 'In finalizer.' })
exit

Output:

In at_exit function.
In finalizer.

Terminates execution immediately, effectively by calling Kernel.exit(false).

If string argument msg is given, it is written to STDERR prior to termination; otherwise, if an exception was raised, prints its message and backtrace.

Waits for a suitable child process to exit, returns its process ID, and sets $? to a Process::Status object containing information on that process. Which child it waits for depends on the value of the given pid:

• Positive integer: Waits for the child process whose process ID is pid:

  pid0 = Process.spawn('ruby', '-e', 'exit 13') # => 230866
  pid1 = Process.spawn('ruby', '-e', 'exit 14') # => 230891
  Process.wait(pid0)                            # => 230866
  $?                                            # => #<Process::Status: pid 230866 exit 13>
  Process.wait(pid1)                            # => 230891
  $?                                            # => #<Process::Status: pid 230891 exit 14>
  Process.wait(pid0)                            # Raises Errno::ECHILD
  

• 0: Waits for any child process whose group ID is the same as that of the current process:

  parent_pgpid = Process.getpgid(Process.pid)
  puts "Parent process group ID is #{parent_pgpid}."
  child0_pid = fork do
    puts "Child 0 pid is #{Process.pid}"
    child0_pgid = Process.getpgid(Process.pid)
    puts "Child 0 process group ID is #{child0_pgid} (same as parent's)."
  end
  child1_pid = fork do
    puts "Child 1 pid is #{Process.pid}"
    Process.setpgid(0, Process.pid)
    child1_pgid = Process.getpgid(Process.pid)
    puts "Child 1 process group ID is #{child1_pgid} (different from parent's)."
  end
  retrieved_pid = Process.wait(0)
  puts "Process.wait(0) returned pid #{retrieved_pid}, which is child 0 pid."
  begin
    Process.wait(0)
  rescue Errno::ECHILD => x
    puts "Raised #{x.class}, because child 1 process group ID differs from parent process group ID."
  end
  

  Output:

  Parent process group ID is 225764.
  Child 0 pid is 225788
  Child 0 process group ID is 225764 (same as parent's).
  Child 1 pid is 225789
  Child 1 process group ID is 225789 (different from parent's).
  Process.wait(0) returned pid 225788, which is child 0 pid.
  Raised Errno::ECHILD, because child 1 process group ID differs from parent process group ID.

• -1 (default): Waits for any child process:

  parent_pgpid = Process.getpgid(Process.pid)
  puts "Parent process group ID is #{parent_pgpid}."
  child0_pid = fork do
    puts "Child 0 pid is #{Process.pid}"
    child0_pgid = Process.getpgid(Process.pid)
    puts "Child 0 process group ID is #{child0_pgid} (same as parent's)."
  end
  child1_pid = fork do
    puts "Child 1 pid is #{Process.pid}"
    Process.setpgid(0, Process.pid)
    child1_pgid = Process.getpgid(Process.pid)
    puts "Child 1 process group ID is #{child1_pgid} (different from parent's)."
    sleep 3 # To force child 1 to exit later than child 0 exit.
  end
  child_pids = [child0_pid, child1_pid]
  retrieved_pid = Process.wait(-1)
  puts child_pids.include?(retrieved_pid)
  retrieved_pid = Process.wait(-1)
  puts child_pids.include?(retrieved_pid)
  

  Output:

  Parent process group ID is 228736.
  Child 0 pid is 228758
  Child 0 process group ID is 228736 (same as parent's).
  Child 1 pid is 228759
  Child 1 process group ID is 228759 (different from parent's).
  true
  true

• Less than -1: Waits for any child whose process group ID is -pid:

  parent_pgpid = Process.getpgid(Process.pid)
  puts "Parent process group ID is #{parent_pgpid}."
  child0_pid = fork do
    puts "Child 0 pid is #{Process.pid}"
    child0_pgid = Process.getpgid(Process.pid)
    puts "Child 0 process group ID is #{child0_pgid} (same as parent's)."
  end
  child1_pid = fork do
    puts "Child 1 pid is #{Process.pid}"
    Process.setpgid(0, Process.pid)
    child1_pgid = Process.getpgid(Process.pid)
    puts "Child 1 process group ID is #{child1_pgid} (different from parent's)."
  end
  sleep 1
  retrieved_pid = Process.wait(-child1_pid)
  puts "Process.wait(-child1_pid) returned pid #{retrieved_pid}, which is child 1 pid."
  begin
    Process.wait(-child1_pid)
  rescue Errno::ECHILD => x
    puts "Raised #{x.class}, because there's no longer a child with process group id #{child1_pid}."
  end
  

  Output:

  Parent process group ID is 230083.
  Child 0 pid is 230108
  Child 0 process group ID is 230083 (same as parent's).
  Child 1 pid is 230109
  Child 1 process group ID is 230109 (different from parent's).
  Process.wait(-child1_pid) returned pid 230109, which is child 1 pid.
  Raised Errno::ECHILD, because there's no longer a child with process group id 230109.

Argument flags should be given as one of the following constants, or as the logical OR of both:

• Process::WNOHANG: Does not block if no child process is available.

• Process:WUNTRACED: May return a stopped child process, even if not yet reported.

Not all flags are available on all platforms.

Raises Errno::ECHILD if there is no suitable child process.

Not available on all platforms.

Process.waitpid is an alias for Process.wait.

Like Process.waitpid, but returns an array containing the child process pid and Process::Status status:

pid = Process.spawn('ruby', '-e', 'exit 13') # => 309581
Process.wait2(pid)
# => [309581, #<Process::Status: pid 309581 exit 13>]

Process.waitpid2 is an alias for Process.waitpid.

Waits for a suitable child process to exit, returns its process ID, and sets $? to a Process::Status object containing information on that process. Which child it waits for depends on the value of the given pid:

• Positive integer: Waits for the child process whose process ID is pid:

  pid0 = Process.spawn('ruby', '-e', 'exit 13') # => 230866
  pid1 = Process.spawn('ruby', '-e', 'exit 14') # => 230891
  Process.wait(pid0)                            # => 230866
  $?                                            # => #<Process::Status: pid 230866 exit 13>
  Process.wait(pid1)                            # => 230891
  $?                                            # => #<Process::Status: pid 230891 exit 14>
  Process.wait(pid0)                            # Raises Errno::ECHILD
  

• 0: Waits for any child process whose group ID is the same as that of the current process:

  parent_pgpid = Process.getpgid(Process.pid)
  puts "Parent process group ID is #{parent_pgpid}."
  child0_pid = fork do
    puts "Child 0 pid is #{Process.pid}"
    child0_pgid = Process.getpgid(Process.pid)
    puts "Child 0 process group ID is #{child0_pgid} (same as parent's)."
  end
  child1_pid = fork do
    puts "Child 1 pid is #{Process.pid}"
    Process.setpgid(0, Process.pid)
    child1_pgid = Process.getpgid(Process.pid)
    puts "Child 1 process group ID is #{child1_pgid} (different from parent's)."
  end
  retrieved_pid = Process.wait(0)
  puts "Process.wait(0) returned pid #{retrieved_pid}, which is child 0 pid."
  begin
    Process.wait(0)
  rescue Errno::ECHILD => x
    puts "Raised #{x.class}, because child 1 process group ID differs from parent process group ID."
  end
  

  Output:

  Parent process group ID is 225764.
  Child 0 pid is 225788
  Child 0 process group ID is 225764 (same as parent's).
  Child 1 pid is 225789
  Child 1 process group ID is 225789 (different from parent's).
  Process.wait(0) returned pid 225788, which is child 0 pid.
  Raised Errno::ECHILD, because child 1 process group ID differs from parent process group ID.

• -1 (default): Waits for any child process:

  parent_pgpid = Process.getpgid(Process.pid)
  puts "Parent process group ID is #{parent_pgpid}."
  child0_pid = fork do
    puts "Child 0 pid is #{Process.pid}"
    child0_pgid = Process.getpgid(Process.pid)
    puts "Child 0 process group ID is #{child0_pgid} (same as parent's)."
  end
  child1_pid = fork do
    puts "Child 1 pid is #{Process.pid}"
    Process.setpgid(0, Process.pid)
    child1_pgid = Process.getpgid(Process.pid)
    puts "Child 1 process group ID is #{child1_pgid} (different from parent's)."
    sleep 3 # To force child 1 to exit later than child 0 exit.
  end
  child_pids = [child0_pid, child1_pid]
  retrieved_pid = Process.wait(-1)
  puts child_pids.include?(retrieved_pid)
  retrieved_pid = Process.wait(-1)
  puts child_pids.include?(retrieved_pid)
  

  Output:

  Parent process group ID is 228736.
  Child 0 pid is 228758
  Child 0 process group ID is 228736 (same as parent's).
  Child 1 pid is 228759
  Child 1 process group ID is 228759 (different from parent's).
  true
  true

• Less than -1: Waits for any child whose process group ID is -pid:

  parent_pgpid = Process.getpgid(Process.pid)
  puts "Parent process group ID is #{parent_pgpid}."
  child0_pid = fork do
    puts "Child 0 pid is #{Process.pid}"
    child0_pgid = Process.getpgid(Process.pid)
    puts "Child 0 process group ID is #{child0_pgid} (same as parent's)."
  end
  child1_pid = fork do
    puts "Child 1 pid is #{Process.pid}"
    Process.setpgid(0, Process.pid)
    child1_pgid = Process.getpgid(Process.pid)
    puts "Child 1 process group ID is #{child1_pgid} (different from parent's)."
  end
  sleep 1
  retrieved_pid = Process.wait(-child1_pid)
  puts "Process.wait(-child1_pid) returned pid #{retrieved_pid}, which is child 1 pid."
  begin
    Process.wait(-child1_pid)
  rescue Errno::ECHILD => x
    puts "Raised #{x.class}, because there's no longer a child with process group id #{child1_pid}."
  end
  

  Output:

  Parent process group ID is 230083.
  Child 0 pid is 230108
  Child 0 process group ID is 230083 (same as parent's).
  Child 1 pid is 230109
  Child 1 process group ID is 230109 (different from parent's).
  Process.wait(-child1_pid) returned pid 230109, which is child 1 pid.
  Raised Errno::ECHILD, because there's no longer a child with process group id 230109.

Argument flags should be given as one of the following constants, or as the logical OR of both:

• Process::WNOHANG: Does not block if no child process is available.

• Process:WUNTRACED: May return a stopped child process, even if not yet reported.

Not all flags are available on all platforms.

Raises Errno::ECHILD if there is no suitable child process.

Not available on all platforms.

Process.waitpid is an alias for Process.wait.

Like Process.waitpid, but returns an array containing the child process pid and Process::Status status:

pid = Process.spawn('ruby', '-e', 'exit 13') # => 309581
Process.wait2(pid)
# => [309581, #<Process::Status: pid 309581 exit 13>]

Process.waitpid2 is an alias for Process.waitpid.

Waits for all children, returns an array of 2-element arrays; each subarray contains the integer pid and Process::Status status for one of the reaped child processes:

pid0 = Process.spawn('ruby', '-e', 'exit 13') # => 325470
pid1 = Process.spawn('ruby', '-e', 'exit 14') # => 325495
Process.waitall
# => [[325470, #<Process::Status: pid 325470 exit 13>], [325495, #<Process::Status: pid 325495 exit 14>]]

Notify the Ruby virtual machine that the boot sequence is finished, and that now is a good time to optimize the application. This is useful for long running applications.

This method is expected to be called at the end of the application boot. If the application is deployed using a pre-forking model, Process.warmup should be called in the original process before the first fork.

The actual optimizations performed are entirely implementation specific and may change in the future without notice.

On CRuby, Process.warmup:

• Performs a major GC.

• Compacts the heap.

• Promotes all surviving objects to the old generation.

• Precomputes the coderange of all strings.

• Frees all empty heap pages and increments the allocatable pages counter by the number of pages freed.

• Invoke malloc_trim if available to free empty malloc pages.

Returns a 2-element array of the current (soft) limit and maximum (hard) limit for the given resource.

Argument resource specifies the resource whose limits are to be returned; see Process.setrlimit.

Each of the returned values cur_limit and max_limit is an integer; see Process.setrlimit.

Example:

Process.getrlimit(:CORE) # => [0, 18446744073709551615]

See Process.setrlimit.

Not available on all platforms.

Sets limits for the current process for the given resource to cur_limit (soft limit) and max_limit (hard limit); returns nil.

Argument resource specifies the resource whose limits are to be set; the argument may be given as a symbol, as a string, or as a constant beginning with Process::RLIMIT_ (e.g., :CORE, 'CORE', or Process::RLIMIT_CORE.

The resources available and supported are system-dependent, and may include (here expressed as symbols):

• :AS: Total available memory (bytes) (SUSv3, NetBSD, FreeBSD, OpenBSD except 4.4BSD-Lite).

• :CORE: Core size (bytes) (SUSv3).

• :CPU: CPU time (seconds) (SUSv3).

• :DATA: Data segment (bytes) (SUSv3).

• :FSIZE: File size (bytes) (SUSv3).

• :MEMLOCK: Total size for mlock(2) (bytes) (4.4BSD, GNU/Linux).

• :MSGQUEUE: Allocation for POSIX message queues (bytes) (GNU/Linux).

• :NICE: Ceiling on process’s nice(2) value (number) (GNU/Linux).

• :NOFILE: File descriptors (number) (SUSv3).

• :NPROC: Number of processes for the user (number) (4.4BSD, GNU/Linux).

• :NPTS: Number of pseudo terminals (number) (FreeBSD).

• :RSS: Resident memory size (bytes) (4.2BSD, GNU/Linux).

• :RTPRIO: Ceiling on the process’s real-time priority (number) (GNU/Linux).

• :RTTIME: CPU time for real-time process (us) (GNU/Linux).

• :SBSIZE: All socket buffers (bytes) (NetBSD, FreeBSD).

• :SIGPENDING: Number of queued signals allowed (signals) (GNU/Linux).

• :STACK: Stack size (bytes) (SUSv3).

Arguments cur_limit and max_limit may be:

• Integers (max_limit should not be smaller than cur_limit).

• Symbol :SAVED_MAX, string 'SAVED_MAX', or constant Process::RLIM_SAVED_MAX: saved maximum limit.

• Symbol :SAVED_CUR, string 'SAVED_CUR', or constant Process::RLIM_SAVED_CUR: saved current limit.

• Symbol :INFINITY, string 'INFINITY', or constant Process::RLIM_INFINITY: no limit on resource.

This example raises the soft limit of core size to the hard limit to try to make core dump possible:

Process.setrlimit(:CORE, Process.getrlimit(:CORE)[1])

Not available on all platforms.

Sets the supplemental group access list; the new list includes:

• The group IDs of those groups to which the user given by username belongs.

• The group ID gid.

Example:

Process.groups                # => [0, 1, 2, 3, 4, 6, 10, 11, 20, 26, 27]
Process.initgroups('me', 30)  # => [30, 6, 10, 11]
Process.groups                # => [30, 6, 10, 11]

Not available on all platforms.

Detaches the current process from its controlling terminal and runs it in the background as system daemon; returns zero.

By default:

• Changes the current working directory to the root directory.

• Redirects $stdin, $stdout, and $stderr to the null device.

If optional argument nochdir is true, does not change the current working directory.

If optional argument noclose is true, does not redirect $stdin, $stdout, or $stderr.

Returns the name of the script being executed. The value is not affected by assigning a new value to $0.

This method first appeared in Ruby 2.1 to serve as a global variable free means to get the script name.

This integer returns the current initial length of the buffer.

This sets the initial length of the buffer to length, if length > 0, otherwise its value isn’t changed.

Returns the form how EC::Point data is encoded as ASN.1.

See also point_conversion_form=.

Sets the form how EC::Point data is encoded as ASN.1 as defined in X9.62.

format can be one of these:

:compressed

Encoded as z||x, where z is an octet indicating which solution of the equation y is. z will be 0x02 or 0x03.

:uncompressed

Encoded as z||x||y, where z is an octet 0x04.

:hybrid

Encodes as z||x||y, where z is an octet indicating which solution of the equation y is. z will be 0x06 or 0x07.

See the OpenSSL documentation for EC_GROUP_set_point_conversion_form()

Get the issuing certificate’s key identifier from the authorityKeyIdentifier extension, as described in RFC5280 Section 4.2.1.1

Returns the binary String keyIdentifier or nil or raises ASN1::ASN1Error.