1 'From Smalltalk/X, Version:2.10.8 on 14-dec-1995 at 18:58:53'                   !

     2 

     3 IdentitySet subclass:#SemaphoreSet

     4 	instanceVariableNames:''

     5 	classVariableNames:''

     6 	poolDictionaries:''

     7 	category:'Kernel-Processes'

     8 !

     9 

    10 !SemaphoreSet class methodsFor:'documentation'!

    11 

    12 documentation

    13 "

    14     SemaphoreSet allow waiting until one of several semaphores become available.

    15 "

    16 !

    17 

    18 examples

    19 "

    20     |sema1 sema2 semaSet proc|

    21 

    22     sema1 := Semaphore new.

    23     sema2 := Semaphore new.

    24     semaSet := SemaphoreSet with:sema1 with:sema2.

    25 

    26     proc := [

    27         [

    28             |ret name|

    29 

    30             ret := semaSet wait.

    31             ret == sema1 ifTrue:[

    32                 name := 'sema1'

    33             ] ifFalse:[ 

    34                 ret == sema2 ifTrue:[

    35                     name := 'sema2'

    36                 ]

    37             ].

    38             Transcript showCr: name, ' raised'.

    39             ret == sema2 ifTrue:[

    40                 proc terminate

    41             ]

    42         ] loop

    43     ] fork.

    44 

    45     (Delay forSeconds:3) wait.

    46     sema1 signal.

    47     (Delay forSeconds:3) wait.

    48     sema2 signal.

    49 "

    50 !

    51 

    52 history

    53     "Created: 14.12.1995 / 12:23:21 / stefan"

    54 ! !

    55 

    56 !SemaphoreSet methodsFor:'wait'!

    57 

    58 wait

    59     |currentProcess gotSema wasBlocked|

    60 

    61     currentProcess := Processor activeProcess.

    62 

    63     wasBlocked := OperatingSystem blockInterrupts.

    64     [

    65         gotSema := self detect:[:sema|

    66             sema checkAndRegisterProcess:currentProcess

    67         ] ifNone:[

    68             currentProcess suspendWithState:#wait.

    69             nil

    70         ].

    71     ] doWhile:[gotSema isNil].

    72 

    73     "

    74       we finaly got one of our semaphores.

    75       Now unregister from any semaphore, we are registered on.

    76     "

    77     gotSema notNil ifTrue:[

    78         self detect:[:sema|

    79             sema == gotSema ifTrue:[

    80                 true

    81             ] ifFalse:[

    82                 sema unregisterProcess:currentProcess.

    83                 false

    84             ]

    85         ] ifNone:[]

    86     ].

    87     wasBlocked ifFalse:[OperatingSystem unblockInterrupts].

    88     ^ gotSema

    89 

    90     "Modified: 14.12.1995 / 13:16:57 / stefan"

    91 ! !

    92 

    93 !SemaphoreSet class methodsFor:'documentation'!

    94 

    95 version

    96 "

    97 $Header: /cvs/stx/stx/libbasic/SemaphoreSet.st,v 1.1 1995-12-14 22:42:02 stefan Exp $

    98 "

    99 ! !