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Unit srfi-18
A simple multithreading package. This threading package follows largely the specification of SRFI-18. For more information see the documentation for SRFI-18.
Notes:
- thread-start! accepts a thunk (a zero argument procedure) as argument, which is equivalent to (thread-start! (make-thread THUNK)).
- thread-sleep! accepts a seconds real number value in addition to a time object.
- When an uncaught exception (i.e. an error) is signalled in a thread other than the primordial thread and warnings are enabled (see: enable-warnings, then a warning message is written to the port that is the value of (current-error-port).
- Blocking I/O will block all threads, except for some socket operations (see the section about the tcp unit). An exception is the read-eval-print loop on UNIX platforms: waiting for input will not block other threads, provided the current input port reads input from a console.
- It is generally not a good idea for one thread to call a continuation created by another thread, if dynamic-wind is involved.
- When more than one thread compete for the current time-slice, the thread that was waiting first will become the next runnable thread.
- The dynamic environment of a thread consists of the following state:
- The current input-, output- and error-port
- The current exception handler
- The values of all current parameters (created by make-parameter)
- Any pending dynamic-wind thunks.
The following procedures are provided, in addition to the procedures defined in SRFI-18:
thread-signal!
[procedure] (thread-signal! THREAD X)
This will cause THREAD to signal the condition X once it is scheduled for execution. After signalling the condition, the thread continues with its normal execution.
thread-quantum
[procedure] (thread-quantum THREAD)
Returns the quantum of THREAD, which is an exact integer specifying the approximate time-slice of the thread.
thread-quantum-set!
[procedure] (thread-quantum-set! THREAD QUANTUM)
Sets the quantum of THREAD to QUANTUM.
thread-suspend!
[procedure] (thread-suspend! THREAD)
Suspends the execution of THREAD until resumed.
thread-resume!
[procedure] (thread-resume! THREAD)
Readys the suspended thread THREAD.
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