Thread

::Thread

Public Class Methods

DEBUG → num click to toggle source

Returns the thread debug level. Available only if compiled with THREAD_DEBUG=-1.

 
               static VALUE
rb_thread_s_debug(void)
{
    return INT2NUM(rb_thread_debug_enabled);
}

DEBUG = num click to toggle source

Sets the thread debug level. Available only if compiled with THREAD_DEBUG=-1.

 
               static VALUE
rb_thread_s_debug_set(VALUE self, VALUE val)
{
    rb_thread_debug_enabled = RTEST(val) ? NUM2INT(val) : 0;
    return val;
}

abort_on_exception → true or false click to toggle source

Returns the status of the global “abort on exception” condition. The default is false. When set to true, or if the global $DEBUG flag is true (perhaps because the command line option -d was specified) all threads will abort (the process will exit(0)) if an exception is raised in any thread. See also Thread::abort_on_exception=.

 
               static VALUE
rb_thread_s_abort_exc(void)
{
    return GET_THREAD()->vm->thread_abort_on_exception ? Qtrue : Qfalse;
}

abort_on_exception= boolean → true or false click to toggle source

When set to true, all threads will abort if an exception is raised. Returns the new state.

Thread.abort_on_exception = true
t1 = Thread.new do
  puts  "In new thread"
  raise "Exception from thread"
end
sleep(1)
puts "not reached"

produces:

In new thread
prog.rb:4: Exception from thread (RuntimeError)
 from prog.rb:2:in `initialize'
 from prog.rb:2:in `new'
 from prog.rb:2

 
               static VALUE
rb_thread_s_abort_exc_set(VALUE self, VALUE val)
{
    rb_secure(4);
    GET_THREAD()->vm->thread_abort_on_exception = RTEST(val);
    return val;
}

current → thread click to toggle source

Returns the currently executing thread.

Thread.current   #=> #<Thread:0x401bdf4c run>

 
               static VALUE
thread_s_current(VALUE klass)
{
    return rb_thread_current();
}

exclusive { block } => obj click to toggle source

Wraps a block in Thread.critical, restoring the original value upon exit from the critical section, and returns the value of the block.

 
               # File prelude.rb, line 26
def self.exclusive
  MUTEX_FOR_THREAD_EXCLUSIVE.synchronize{
    yield
  }
end

exit → thread click to toggle source

Terminates the currently running thread and schedules another thread to be run. If this thread is already marked to be killed, exit returns the Thread. If this is the main thread, or the last thread, exit the process.

 
               static VALUE
rb_thread_exit(void)
{
    return rb_thread_kill(GET_THREAD()->self);
}

fork([args]*) {|args| block } → thread click to toggle source

Basically the same as Thread::new. However, if class Thread is subclassed, then calling start in that subclass will not invoke the subclass’s initialize method.

 
               static VALUE
thread_start(VALUE klass, VALUE args)
{
    return thread_create_core(rb_thread_alloc(klass), args, 0);
}

kill(thread) → thread click to toggle source

Causes the given thread to exit (see Thread::exit).

count = 0
a = Thread.new { loop { count += 1 } }
sleep(0.1)       #=> 0
Thread.kill(a)   #=> #<Thread:0x401b3d30 dead>
count            #=> 93947
a.alive?         #=> false

 
               static VALUE
rb_thread_s_kill(VALUE obj, VALUE th)
{
    return rb_thread_kill(th);
}

list → array click to toggle source

Returns an array of Thread objects for all threads that are either runnable or stopped.

Thread.new { sleep(200) }
Thread.new { 1000000.times {|i| i*i } }
Thread.new { Thread.stop }
Thread.list.each {|t| p t}

produces:

#<Thread:0x401b3e84 sleep>
#<Thread:0x401b3f38 run>
#<Thread:0x401b3fb0 sleep>
#<Thread:0x401bdf4c run>

 
               VALUE
rb_thread_list(void)
{
    VALUE ary = rb_ary_new();
    st_foreach(GET_THREAD()->vm->living_threads, thread_list_i, ary);
    return ary;
}

main → thread click to toggle source

Returns the main thread.

 
               static VALUE
rb_thread_s_main(VALUE klass)
{
    return rb_thread_main();
}

pass → nil click to toggle source

Give the thread scheduler a hint to pass execution to another thread. A running thread may or may not switch, it depends on OS and processor.

 
               static VALUE
thread_s_pass(VALUE klass)
{
    rb_thread_schedule();
    return Qnil;
}

start([args]*) {|args| block } → thread click to toggle source

Basically the same as Thread::new. However, if class Thread is subclassed, then calling start in that subclass will not invoke the subclass’s initialize method.

 
               static VALUE
thread_start(VALUE klass, VALUE args)
{
    return thread_create_core(rb_thread_alloc(klass), args, 0);
}

stop → nil click to toggle source

Stops execution of the current thread, putting it into a “sleep” state, and schedules execution of another thread.

a = Thread.new { print "a"; Thread.stop; print "c" }
sleep 0.1 while a.status!='sleep'
print "b"
a.run
a.join

produces:

abc

 
               VALUE
rb_thread_stop(void)
{
    if (rb_thread_alone()) {
        rb_raise(rb_eThreadError,
                 "stopping only thread\n\tnote: use sleep to stop forever");
    }
    rb_thread_sleep_deadly();
    return Qnil;
}

Public Instance Methods

thr[sym] → obj or nil click to toggle source

Attribute Reference—Returns the value of a thread-local variable, using either a symbol or a string name. If the specified variable does not exist, returns nil.

[
  Thread.new { Thread.current["name"] = "A" },
  Thread.new { Thread.current[:name]  = "B" },
  Thread.new { Thread.current["name"] = "C" }
].each do |th|
  th.join
  puts "#{th.inspect}: #{th[:name]}"
end

produces:

#<Thread:0x00000002a54220 dead>: A
#<Thread:0x00000002a541a8 dead>: B
#<Thread:0x00000002a54130 dead>: C

 
               static VALUE
rb_thread_aref(VALUE thread, VALUE id)
{
    return rb_thread_local_aref(thread, rb_to_id(id));
}

thr[sym] = obj → obj click to toggle source

Attribute Assignment—Sets or creates the value of a thread-local variable, using either a symbol or a string. See also Thread#[].

 
               static VALUE
rb_thread_aset(VALUE self, VALUE id, VALUE val)
{
    return rb_thread_local_aset(self, rb_to_id(id), val);
}

abort_on_exception → true or false click to toggle source

Returns the status of the thread-local “abort on exception” condition for thr. The default is false. See also Thread::abort_on_exception=.

 
               static VALUE
rb_thread_abort_exc(VALUE thread)
{
    rb_thread_t *th;
    GetThreadPtr(thread, th);
    return th->abort_on_exception ? Qtrue : Qfalse;
}

abort_on_exception= boolean → true or false click to toggle source

When set to true, causes all threads (including the main program) to abort if an exception is raised in thr. The process will effectively exit(0).

 
               static VALUE
rb_thread_abort_exc_set(VALUE thread, VALUE val)
{
    rb_thread_t *th;
    rb_secure(4);

    GetThreadPtr(thread, th);
    th->abort_on_exception = RTEST(val);
    return val;
}

add_trace_func(proc) → proc click to toggle source

Adds proc as a handler for tracing. See Thread#set_trace_func and set_trace_func.

 
               static VALUE
thread_add_trace_func_m(VALUE obj, VALUE trace)
{
    rb_thread_t *th;
    GetThreadPtr(obj, th);
    thread_add_trace_func(th, trace);
    return trace;
}

alive? → true or false click to toggle source

Returns true if thr is running or sleeping.

thr = Thread.new { }
thr.join                #=> #<Thread:0x401b3fb0 dead>
Thread.current.alive?   #=> true
thr.alive?              #=> false

 
               static VALUE
rb_thread_alive_p(VALUE thread)
{
    rb_thread_t *th;
    GetThreadPtr(thread, th);

    if (rb_threadptr_dead(th))
        return Qfalse;
    return Qtrue;
}

backtrace → array click to toggle source

Returns the current back trace of the thr.

 
               static VALUE
rb_thread_backtrace_m(VALUE thval)
{
    return rb_thread_backtrace(thval);
}

exit → thr or nil click to toggle source

kill → thr or nil

terminate → thr or nil

Terminates thr and schedules another thread to be run. If this thread is already marked to be killed, exit returns the Thread. If this is the main thread, or the last thread, exits the process.

 
               VALUE
rb_thread_kill(VALUE thread)
{
    rb_thread_t *th;

    GetThreadPtr(thread, th);

    if (th != GET_THREAD() && th->safe_level < 4) {
        rb_secure(4);
    }
    if (th->status == THREAD_TO_KILL || th->status == THREAD_KILLED) {
        return thread;
    }
    if (th == th->vm->main_thread) {
        rb_exit(EXIT_SUCCESS);
    }

    thread_debug("rb_thread_kill: %p (%p)\n", (void *)th, (void *)th->thread_id);

    rb_threadptr_interrupt(th);
    th->thrown_errinfo = eKillSignal;
    th->status = THREAD_TO_KILL;

    return thread;
}

group → thgrp or nil click to toggle source

Returns the ThreadGroup which contains thr, or nil if the thread is not a member of any group.

Thread.main.group   #=> #<ThreadGroup:0x4029d914>

 
               VALUE
rb_thread_group(VALUE thread)
{
    rb_thread_t *th;
    VALUE group;
    GetThreadPtr(thread, th);
    group = th->thgroup;

    if (!group) {
        group = Qnil;
    }
    return group;
}

inspect → string click to toggle source

Dump the name, id, and status of thr to a string.

 
               static VALUE
rb_thread_inspect(VALUE thread)
{
    const char *cname = rb_obj_classname(thread);
    rb_thread_t *th;
    const char *status;
    VALUE str;

    GetThreadPtr(thread, th);
    status = thread_status_name(th->status);
    str = rb_sprintf("#<%s:%p %s>", cname, (void *)thread, status);
    OBJ_INFECT(str, thread);

    return str;
}

join → thr click to toggle source

join(limit) → thr

The calling thread will suspend execution and run thr. Does not return until thr exits or until limit seconds have passed. If the time limit expires, nil will be returned, otherwise thr is returned.

Any threads not joined will be killed when the main program exits. If thr had previously raised an exception and the abort_on_exception and $DEBUG flags are not set (so the exception has not yet been processed) it will be processed at this time.

a = Thread.new { print "a"; sleep(10); print "b"; print "c" }
x = Thread.new { print "x"; Thread.pass; print "y"; print "z" }
x.join # Let x thread finish, a will be killed on exit.

produces:

axyz

The following example illustrates the limit parameter.

y = Thread.new { 4.times { sleep 0.1; puts 'tick... ' }}
puts "Waiting" until y.join(0.15)

produces:

tick...
Waiting
tick...
Waitingtick...

tick...

 
               static VALUE
thread_join_m(int argc, VALUE *argv, VALUE self)
{
    rb_thread_t *target_th;
    double delay = DELAY_INFTY;
    VALUE limit;

    GetThreadPtr(self, target_th);

    rb_scan_args(argc, argv, "01", &limit);
    if (!NIL_P(limit)) {
        delay = rb_num2dbl(limit);
    }

    return thread_join(target_th, delay);
}

key?(sym) → true or false click to toggle source

Returns true if the given string (or symbol) exists as a thread-local variable.

me = Thread.current
me[:oliver] = "a"
me.key?(:oliver)    #=> true
me.key?(:stanley)   #=> false

 
               static VALUE
rb_thread_key_p(VALUE self, VALUE key)
{
    rb_thread_t *th;
    ID id = rb_to_id(key);

    GetThreadPtr(self, th);

    if (!th->local_storage) {
        return Qfalse;
    }
    if (st_lookup(th->local_storage, id, 0)) {
        return Qtrue;
    }
    return Qfalse;
}

keys → array click to toggle source

Returns an an array of the names of the thread-local variables (as Symbols).

thr = Thread.new do
  Thread.current[:cat] = 'meow'
  Thread.current["dog"] = 'woof'
end
thr.join   #=> #<Thread:0x401b3f10 dead>
thr.keys   #=> [:dog, :cat]

 
               static VALUE
rb_thread_keys(VALUE self)
{
    rb_thread_t *th;
    VALUE ary = rb_ary_new();
    GetThreadPtr(self, th);

    if (th->local_storage) {
        st_foreach(th->local_storage, thread_keys_i, ary);
    }
    return ary;
}

exit → thr or nil click to toggle source

kill → thr or nil

terminate → thr or nil

Terminates thr and schedules another thread to be run. If this thread is already marked to be killed, exit returns the Thread. If this is the main thread, or the last thread, exits the process.

 
               VALUE
rb_thread_kill(VALUE thread)
{
    rb_thread_t *th;

    GetThreadPtr(thread, th);

    if (th != GET_THREAD() && th->safe_level < 4) {
        rb_secure(4);
    }
    if (th->status == THREAD_TO_KILL || th->status == THREAD_KILLED) {
        return thread;
    }
    if (th == th->vm->main_thread) {
        rb_exit(EXIT_SUCCESS);
    }

    thread_debug("rb_thread_kill: %p (%p)\n", (void *)th, (void *)th->thread_id);

    rb_threadptr_interrupt(th);
    th->thrown_errinfo = eKillSignal;
    th->status = THREAD_TO_KILL;

    return thread;
}

priority → integer click to toggle source

Returns the priority of thr. Default is inherited from the current thread which creating the new thread, or zero for the initial main thread; higher-priority thread will run more frequently than lower-priority threads (but lower-priority threads can also run).

This is just hint for Ruby thread scheduler. It may be ignored on some platform.

Thread.current.priority   #=> 0

 
               static VALUE
rb_thread_priority(VALUE thread)
{
    rb_thread_t *th;
    GetThreadPtr(thread, th);
    return INT2NUM(th->priority);
}

priority= integer → thr click to toggle source

Sets the priority of thr to integer. Higher-priority threads will run more frequently than lower-priority threads (but lower-priority threads can also run).

This is just hint for Ruby thread scheduler. It may be ignored on some platform.

count1 = count2 = 0
a = Thread.new do
      loop { count1 += 1 }
    end
a.priority = -1

b = Thread.new do
      loop { count2 += 1 }
    end
b.priority = -2
sleep 1   #=> 1
count1    #=> 622504
count2    #=> 5832

 
               static VALUE
rb_thread_priority_set(VALUE thread, VALUE prio)
{
    rb_thread_t *th;
    int priority;
    GetThreadPtr(thread, th);

    rb_secure(4);

#if USE_NATIVE_THREAD_PRIORITY
    th->priority = NUM2INT(prio);
    native_thread_apply_priority(th);
#else
    priority = NUM2INT(prio);
    if (priority > RUBY_THREAD_PRIORITY_MAX) {
        priority = RUBY_THREAD_PRIORITY_MAX;
    }
    else if (priority < RUBY_THREAD_PRIORITY_MIN) {
        priority = RUBY_THREAD_PRIORITY_MIN;
    }
    th->priority = priority;
#endif
    return INT2NUM(th->priority);
}

raise click to toggle source

raise(string)

raise(exception [, string [, array]])

Raises an exception (see Kernel::raise) from thr. The caller does not have to be thr.

Thread.abort_on_exception = true
a = Thread.new { sleep(200) }
a.raise("Gotcha")

produces:

prog.rb:3: Gotcha (RuntimeError)
 from prog.rb:2:in `initialize'
 from prog.rb:2:in `new'
 from prog.rb:2

 
               static VALUE
thread_raise_m(int argc, VALUE *argv, VALUE self)
{
    rb_thread_t *th;
    GetThreadPtr(self, th);
    rb_threadptr_raise(th, argc, argv);
    return Qnil;
}

run → thr click to toggle source

Wakes up thr, making it eligible for scheduling.

a = Thread.new { puts "a"; Thread.stop; puts "c" }
sleep 0.1 while a.status!='sleep'
puts "Got here"
a.run
a.join

produces:

a
Got here
c

 
               VALUE
rb_thread_run(VALUE thread)
{
    rb_thread_wakeup(thread);
    rb_thread_schedule();
    return thread;
}

safe_level → integer click to toggle source

Returns the safe level in effect for thr. Setting thread-local safe levels can help when implementing sandboxes which run insecure code.

thr = Thread.new { $SAFE = 3; sleep }
Thread.current.safe_level   #=> 0
thr.safe_level              #=> 3

 
               static VALUE
rb_thread_safe_level(VALUE thread)
{
    rb_thread_t *th;
    GetThreadPtr(thread, th);

    return INT2NUM(th->safe_level);
}

set_trace_func(proc) → proc click to toggle source

set_trace_func(nil) → nil

Establishes proc on thr as the handler for tracing, or disables tracing if the parameter is nil. See set_trace_func.

 
               static VALUE
thread_set_trace_func_m(VALUE obj, VALUE trace)
{
    rb_thread_t *th;
    GetThreadPtr(obj, th);
    rb_threadptr_remove_event_hook(th, call_trace_func);

    if (NIL_P(trace)) {
        th->tracing = EVENT_RUNNING_NOTHING;
        return Qnil;
    }
    thread_add_trace_func(th, trace);
    return trace;
}

status → string, false or nil click to toggle source

Returns the status of thr: “sleep” if thr is sleeping or waiting on I/O, “run” if thr is executing, “aborting” if thr is aborting, false if thr terminated normally, and nil if thr terminated with an exception.

a = Thread.new { raise("die now") }
b = Thread.new { Thread.stop }
c = Thread.new { Thread.exit }
d = Thread.new { sleep }
d.kill                  #=> #<Thread:0x401b3678 aborting>
a.status                #=> nil
b.status                #=> "sleep"
c.status                #=> false
d.status                #=> "aborting"
Thread.current.status   #=> "run"

 
               static VALUE
rb_thread_status(VALUE thread)
{
    rb_thread_t *th;
    GetThreadPtr(thread, th);

    if (rb_threadptr_dead(th)) {
        if (!NIL_P(th->errinfo) && !FIXNUM_P(th->errinfo)
            /* TODO */ ) {
            return Qnil;
        }
        return Qfalse;
    }
    return rb_str_new2(thread_status_name(th->status));
}

stop? → true or false click to toggle source

Returns true if thr is dead or sleeping.

a = Thread.new { Thread.stop }
b = Thread.current
a.stop?   #=> true
b.stop?   #=> false

 
               static VALUE
rb_thread_stop_p(VALUE thread)
{
    rb_thread_t *th;
    GetThreadPtr(thread, th);

    if (rb_threadptr_dead(th))
        return Qtrue;
    if (th->status == THREAD_STOPPED || th->status == THREAD_STOPPED_FOREVER)
        return Qtrue;
    return Qfalse;
}

terminate → thr or nil click to toggle source

Terminates thr and schedules another thread to be run. If this thread is already marked to be killed, exit returns the Thread. If this is the main thread, or the last thread, exits the process.

 
               VALUE
rb_thread_kill(VALUE thread)
{
    rb_thread_t *th;

    GetThreadPtr(thread, th);

    if (th != GET_THREAD() && th->safe_level < 4) {
        rb_secure(4);
    }
    if (th->status == THREAD_TO_KILL || th->status == THREAD_KILLED) {
        return thread;
    }
    if (th == th->vm->main_thread) {
        rb_exit(EXIT_SUCCESS);
    }

    thread_debug("rb_thread_kill: %p (%p)\n", (void *)th, (void *)th->thread_id);

    rb_threadptr_interrupt(th);
    th->thrown_errinfo = eKillSignal;
    th->status = THREAD_TO_KILL;

    return thread;
}

value → obj click to toggle source

Waits for thr to complete (via Thread#join) and returns its value.

a = Thread.new { 2 + 2 }
a.value   #=> 4

 
               static VALUE
thread_value(VALUE self)
{
    rb_thread_t *th;
    GetThreadPtr(self, th);
    thread_join(th, DELAY_INFTY);
    return th->value;
}

wakeup → thr click to toggle source

Marks thr as eligible for scheduling (it may still remain blocked on I/O, however). Does not invoke the scheduler (see Thread#run).

c = Thread.new { Thread.stop; puts "hey!" }
sleep 0.1 while c.status!='sleep'
c.wakeup
c.join

produces:

hey!

 
               VALUE
rb_thread_wakeup(VALUE thread)
{
    if (!RTEST(rb_thread_wakeup_alive(thread))) {
        rb_raise(rb_eThreadError, "killed thread");
    }
    return thread;
}

Home Classes Methods

In Files

Parent

Methods

Files

Class/Module Index

Thread

Public Class Methods

Public Instance Methods