SYNOPSIS

methods to add posix (fcntl based and nfs safe) locking to the builtin File class

URLS:

raa.ruby-lang.org/project/posixlock/ www.codeforpeople.com/lib/ruby/posixlock/

EXAMPLES:

1.

File.open('even_an_nfs_mounted_file','r+').posixlock File::LOCK_EX

2.

File.open('even_an_nfs_mounted_file','r+').lockf File::F_LOCK, 0

3.

open('even_an_nfs_mounted_file','r') do |f|
  f.lockf File::F_LOCKR, 42 
end

4.

f = open 'foo', 'r+'

if((pid = f.lockf File::F_TEST, 0))
  STDERR.puts "process <#{ pid }> prevents write lock"
end

5.

f = open 'foo', 'r'

if((pid = f.lockf File::F_TESTR, 0))
  STDERR.puts "process <#{ pid }> prevents read lock"
end

DOCS

posixlock.c

File#posixlock has an identical interface to the builtin File#flock

for File#lockf see man (3) lockf

the additional flags

File::F_LOCKR
File::F_LOCKW
File::F_TLOCKR
File::F_TLOCKW
File::F_TESTR
File::F_TESTW

have the obvious meaning

AUTHOR

ara.t.howard@noaa.gov

BUGS

> 1

HISTORY

1.0.0: changed behaviour so that, instead of replacing flock, two new methods are added: File#posixlock gives access to read/write locks with an interface identical to File#flock, and File#lockf gives access to a lockf impl similar to the one posix specifies with added functionality for read locks. the biggest difference between the two methods is that lockf will throw errors for errno’s like EAGAIN, EACCESS, etc.

0.0.0: initial version