Built-in Module thread

This module provides low-level primitives for working with multiple threads (a.k.a. light-weight processes or tasks) --- multiple threads of control sharing their global data space. For synchronization, simple locks (a.k.a. mutexes or <#2866#>binary semaphores<#2866#>) are provided.

The module is optional and supported on SGI and Sun Sparc systems only.

It defines the following constant and functions:

#excdesc2869#

#funcdesc2872#

#funcdesc2878#

#funcdesc2884#

#funcdesc2891#

Lock objects have the following methods:

#funcdesc2897#

#funcdesc2903#

#funcdesc2907#

Caveats:

• Threads interact strangely with interrupts: the KeyboardInterrupt exception will be received by an arbitrary thread.

• Calling sys.exit(status) or executing raise SystemExit, status is almost equivalent to calling thread.exit_prog(status), except that the former ways of exiting the entire program do honor finally clauses in the current thread (but not in other threads).

• Not all built-in functions that may block waiting for I/O allow other threads to run, although the most popular ones (sleep, read, select) work as expected.