Alarm::Concurrent 1.0

Alarm::Concurrent is a Perl module that allows multiple, concurrent alarms. This module is an attempt to enhance Perls built-in alarm/$SIG{ALRM} functionality. This function, and its associated signal handler, allow you to arrange for your program to receive a SIGALRM signal, which you can then catch and deal with appropriately. Unfortunately, due to the nature of the design of these signals (at the OS level), you can only have one alarm and handler active at any given time. Thats where this module comes in. This module allows you to define multiple alarms, each with an associated handler. These alarms are sequenced (in a queue) but concurrent, which means that their order is preserved but they always go off as their set time expires, regardless of the state of the other alarms. (If youd like to have the alarms only go off in the order you set them, see Alarm::Queued.) To set an alarm, call the setalarm() function with the set time of the alarm and a reference to the subroutine to be called when the alarm goes off. You can then go on with your program and the alarm will be called after the set time has passed. It is also possible to set an alarm that does not have a handler associated with it using Alarm::Concurrent::alarm(). (This function can also be imported into your namespace, in which case it will replace Perls built-in alarm for your package only.) If an alarm that does not have a handler associated with it goes off, the default handler, pointed to by $Alarm::Concurrent::DEFAULT_HANLDER, is called. You can change the default handler by assigning to this variable. The default $Alarm::Concurrent::DEFAULT_HANDLER simply dies with the message "Alarm clock!n". IMPORT/EXPORT No methods are exported by default but you can import any of the functions in the FUNCTIONS section. You can also import the special tag :ALL which will import all the functions in the FUNCTIONS section (except Alarm::Concurrent::restore()). OVERRIDE If you import the special tag :OVERRIDE, this module will override Perls built-in alarm function for every namespace and it will take over Perls magic %SIG variable, changing any attempts to read or write $SIG{ALRM} into calls to gethandler() and sethandler(), respectively (reading and writing to other keys in %SIG is unaffected). This can be useful when you are calling code that tries to set its own alarm "the old fashioned way." It can also, however, be dangerous. Overriding alarm is documented and should be stable but taking over %SIG is more risky (see CAVEATS). Note that if you do not override alarm and %SIG, any code you use that sets "legacy alarms" will disable all of your concurrent alarms. You can call Alarm::Concurrent::restore() to reinstall the Alarm::Concurrent handler. This function can not be imported..

Requirements:	No special requirements
Platforms:	Linux
Keyword:	Alarm,  Alarmconcurrent,  Alarms,  Concurrent,  Handler,  Libraries,  Module,  Multiple,  Perl Module,  Programming,  Sig
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