1.16. _thread — Low-level threading API

This module provides low-level primitives for working with multiple threads - multiple threads of control sharing their global data space. For synchronization, simple locks (also called mutexes or binary semaphores) are provided.

A thread created by this module is a Simba thread. The classes sync.Event and sync.Queue can be used for synchronization in addition to the simple locks.

_thread.start_new_thread(function, args[, kwargs])

Start a new thread and return its identifier. The thread executes the function function with the argument list args (which must be a tuple). The optional kwargs argument specifies a dictionary of keyword arguments. When the function returns, the thread silently exits.

_thread.exit()

Raise the SystemExit exception. When not caught, this will cause the thread to exit silently.

_thread.allocate_lock()

Return a new lock object. Methods of locks are described below. The lock is initially unlocked.

_thread.get_ident()

Return the thread identifier of the current thread. This is a nonzero integer. Its value has no direct meaning; it is intended as a magic cookie to be used e.g. to index a dictionary of thread-specific data. Thread identifiers may be recycled when a thread exits and another thread is created.

_thread.stack_size([size])

Return the thread stack size used when creating new threads.

class _thread.LockType
acquire([waitflag])

Without the optional argument, this method acquires the lock unconditionally, if necessary waiting until it is released by another thread (only one thread at a time can acquire a lock — that’s their reason for existence). If the integer waitflag argument is present, the action depends on its value: if it is zero, the lock is only acquired if it can be acquired immediately without waiting, while if it is nonzero, the lock is acquired unconditionally as before. The return value is True if the lock is acquired successfully, False if not.

release()

Releases the lock. The lock must have been acquired earlier, but not necessarily by the same thread.

locked()

Return the status of the lock: True if it has been acquired by some thread, False if not.