Semaphore Readers Writers Pattern or Light switch
Synopsis
use Semaphore::ReadersWriters;
my Semaphore::ReadersWriters $rw .= new;
$rw.add-mutex-names('shv');
my $shared-var = 10;
# After creating threads ...
# Some writer thread
$rw.writer( 'shv', {$shared-var += 2});
# Some reader thread
say 'Shared var is ', $rw.reader( 'shv', {$shared-var;});
Documentation
The Markdown files in this package uses the atom plugin Markdown Preview Enhanced. E.g. the synopsis can be run by placing the cursor in the code and type `shift-enter' or, if not possible, look for the readme pdf in doc)
TODO
- Implement other variants of this pattern.
- Readers priority variant.
- No writer starvation variant.
- Document return value restrictions. Only items, no List.
CHANGELOG
See semantic versioning. Please note point 4. on that page: Major version zero (0.y.z) is for initial development. Anything may change at any time. The public API should not be considered stable.
- 0.2.6
- Methods
reader and writer returned a failure object when things are wrong. This poses a problem in some situations. Now it will throw an exception.
- 0.2.5
- Changed last method into check-mutex-names() to test for more than one name.
- 0.2.4
- Added convenience method check-mutex-name().
- 0.2.3
- add-mutex-names throws an exception when keys are reused
- 0.2.2
- Added $.debug to show messages about the actions. This will be deprecated later when I am confident enough that everything works well enough.
- 0.2.1
- Removed debugging texts to publish class
- 0.2.0
- Documentation
- Bugfixes, hangups caused by overuse of same semaphores. Added more semaphores per critical section.
- Preparations for other variations of this pattern
- 0.1.0 First tests
- 0.0.1 Setup
Other info
Perl6 version
Tested on the latest version of perl6 on moarvm
Install
Install package using zef
zef install Semaphore::ReadersWriters
Author
Marcel Timmerman
MARTIMM on github