ThreadGroup provides a means of keeping track of a number of threads as a group.
A given Thread object can only belong to one ThreadGroup at a time; adding a thread to a new group will remove it from any previous group.
Newly created threads belong to the same group as the thread from which they were created.
The default ThreadGroup created when Ruby starts; all Threads belong to it by default.
static VALUE
thgroup_add(VALUE group, VALUE thread)
{
rb_thread_t *target_th = rb_thread_ptr(thread);
struct thgroup *data;
if (OBJ_FROZEN(group)) {
rb_raise(rb_eThreadError, "can't move to the frozen thread group");
}
TypedData_Get_Struct(group, struct thgroup, &thgroup_data_type, data);
if (data->enclosed) {
rb_raise(rb_eThreadError, "can't move to the enclosed thread group");
}
if (OBJ_FROZEN(target_th->thgroup)) {
rb_raise(rb_eThreadError, "can't move from the frozen thread group");
}
TypedData_Get_Struct(target_th->thgroup, struct thgroup, &thgroup_data_type, data);
if (data->enclosed) {
rb_raise(rb_eThreadError,
"can't move from the enclosed thread group");
}
target_th->thgroup = group;
return group;
}
Adds the given thread to this group, removing it from any other group to which it may have previously been a member.
puts "Initial group is #{ThreadGroup::Default.list}" tg = ThreadGroup.new t1 = Thread.new { sleep } t2 = Thread.new { sleep } puts "t1 is #{t1}" puts "t2 is #{t2}" tg.add(t1) puts "Initial group now #{ThreadGroup::Default.list}" puts "tg group now #{tg.list}"
This will produce:
Initial group is #<Thread:0x401bdf4c> t1 is #<Thread:0x401b3c90> t2 is #<Thread:0x401b3c18> Initial group now #<Thread:0x401b3c18>#<Thread:0x401bdf4c> tg group now #<Thread:0x401b3c90>
static VALUE
thgroup_enclose(VALUE group)
{
struct thgroup *data;
TypedData_Get_Struct(group, struct thgroup, &thgroup_data_type, data);
data->enclosed = 1;
return group;
}
Prevents threads from being added to or removed from the receiving ThreadGroup.
New threads can still be started in an enclosed ThreadGroup.
ThreadGroup::Default.enclose #=> #<ThreadGroup:0x4029d914> thr = Thread.new { Thread.stop } #=> #<Thread:0x402a7210 sleep> tg = ThreadGroup.new #=> #<ThreadGroup:0x402752d4> tg.add thr #=> ThreadError: can't move from the enclosed thread group
static VALUE
thgroup_enclosed_p(VALUE group)
{
struct thgroup *data;
TypedData_Get_Struct(group, struct thgroup, &thgroup_data_type, data);
return RBOOL(data->enclosed);
}
Returns true if the thgrp is enclosed. See also ThreadGroup#enclose.
static VALUE
thgroup_list(VALUE group)
{
VALUE ary = rb_ary_new();
rb_thread_t *th = 0;
rb_ractor_t *r = GET_RACTOR();
list_for_each(&r->threads.set, th, lt_node) {
if (th->thgroup == group) {
rb_ary_push(ary, th->self);
}
}
return ary;
}
Returns an array of all existing Thread objects that belong to this group.
ThreadGroup::Default.list #=> [#<Thread:0x401bdf4c run>]