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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.


The following procedures are provided, in addition to the procedures defined in SRFI-18:


[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.


[procedure] (thread-quantum THREAD)

Returns the quantum of THREAD, which is an exact integer specifying the approximate time-slice of the thread in milliseconds.


[procedure] (thread-quantum-set! THREAD QUANTUM)

Sets the quantum of THREAD to QUANTUM.


[procedure] (thread-suspend! THREAD)

Suspends the execution of THREAD until resumed.


[procedure] (thread-resume! THREAD)

Readies the suspended thread THREAD.


[procedure] (thread-wait-for-i/o! FD [MODE])

Suspends the current thread until input (MODE is #:input), output (MODE is #:output) or both (MODE is #:all) is available. FD should be a file-descriptor (not a port!) open for input or output, respectively.


[procedure] (time->milliseconds TIME)

Converts a time object (as created via current-time) into an exact integer representing the number of milliseconds since process startup.


[procedure] (milliseconds->time ms)

Converts into a time object an exact integer representing the number of milliseconds since process startup.

This procedure may be useful in combination with thread-sleep! when your compilation unit is using (declare fixnum-arithmetic). In that case you won't be able to pass an inexact value to thread-sleep!, but you can do the following:

(define (thread-sleep!/ms ms)
   (milliseconds->time (+ ms (current-milliseconds)))))

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