Get the ‘current’ server.
In the context of execution taking place within the main thread of a dRuby server (typically, as a result of a remote call on the server or one of its objects), the current server is that server. Otherwise, the current server is the primary server.
If the above rule fails to find a server, a DRbServerNotFound error is raised.
Registers server with DRb.
This is called when a new DRb::DRbServer is created.
If there is no primary server then server becomes the primary server.
Example:
require 'drb' s = DRb::DRbServer.new # automatically calls regist_server DRb.fetch_server s.uri #=> #<DRb::DRbServer:0x...>
Registers server with DRb.
This is called when a new DRb::DRbServer is created.
If there is no primary server then server becomes the primary server.
Example:
require 'drb' s = DRb::DRbServer.new # automatically calls regist_server DRb.fetch_server s.uri #=> #<DRb::DRbServer:0x...>
Removes server from the list of registered servers.
Removes server from the list of registered servers.
Retrieves the server with the given uri.
See also regist_server and remove_server.
Add observer as an observer on this object. So that it will receive notifications.
observer
the object that will be notified of changes.
func
Symbol naming the method that will be called when this Observable has changes.
This method must return true for observer.respond_to? and will receive *arg when notify_observers is called, where *arg is the value passed to notify_observers by this Observable
Remove observer as an observer on this object so that it will no longer receive notifications.
observer
An observer of this Observable
Remove all observers associated with this object.
Return the number of observers associated with this object.
Notify observers of a change in state if this object’s changed state is true.
This will invoke the method named in add_observer, passing *arg. The changed state is then set to false.
*arg
Any arguments to pass to the observers.
A Gem::Version for the currently running RubyGems
Returns a time returned by POSIX clock_gettime() function.
p Process.clock_gettime(Process::CLOCK_MONOTONIC) #=> 896053.968060096
clock_id specifies a kind of clock. It is specified as a constant which begins with Process::CLOCK_ such as Process::CLOCK_REALTIME and Process::CLOCK_MONOTONIC.
The supported constants depends on OS and version. Ruby provides following types of clock_id if available.
CLOCK_REALTIME
SUSv2 to 4, Linux 2.5.63, FreeBSD 3.0, NetBSD 2.0, OpenBSD 2.1, macOS 10.12
CLOCK_MONOTONIC
SUSv3 to 4, Linux 2.5.63, FreeBSD 3.0, NetBSD 2.0, OpenBSD 3.4, macOS 10.12
CLOCK_PROCESS_CPUTIME_ID
SUSv3 to 4, Linux 2.5.63, OpenBSD 5.4, macOS 10.12
CLOCK_THREAD_CPUTIME_ID
SUSv3 to 4, Linux 2.5.63, FreeBSD 7.1, OpenBSD 5.4, macOS 10.12
CLOCK_VIRTUAL
FreeBSD 3.0, OpenBSD 2.1
CLOCK_PROF
FreeBSD 3.0, OpenBSD 2.1
CLOCK_REALTIME_FAST
FreeBSD 8.1
CLOCK_REALTIME_PRECISE
FreeBSD 8.1
CLOCK_REALTIME_COARSE
Linux 2.6.32
CLOCK_REALTIME_ALARM
Linux 3.0
CLOCK_MONOTONIC_FAST
FreeBSD 8.1
CLOCK_MONOTONIC_PRECISE
FreeBSD 8.1
CLOCK_MONOTONIC_COARSE
Linux 2.6.32
CLOCK_MONOTONIC_RAW
Linux 2.6.28, macOS 10.12
CLOCK_MONOTONIC_RAW_APPROX
macOS 10.12
CLOCK_BOOTTIME
Linux 2.6.39
CLOCK_BOOTTIME_ALARM
Linux 3.0
CLOCK_UPTIME
FreeBSD 7.0, OpenBSD 5.5
CLOCK_UPTIME_FAST
FreeBSD 8.1
CLOCK_UPTIME_RAW
macOS 10.12
CLOCK_UPTIME_RAW_APPROX
macOS 10.12
CLOCK_UPTIME_PRECISE
FreeBSD 8.1
CLOCK_SECOND
FreeBSD 8.1
Note that SUS stands for Single Unix Specification. SUS contains POSIX and clock_gettime is defined in the POSIX part. SUS defines CLOCK_REALTIME mandatory but CLOCK_MONOTONIC, CLOCK_PROCESS_CPUTIME_ID and CLOCK_THREAD_CPUTIME_ID are optional.
Also, several symbols are accepted as clock_id. There are emulations for clock_gettime().
For example, Process::CLOCK_REALTIME is defined as :GETTIMEOFDAY_BASED_CLOCK_REALTIME when clock_gettime() is not available.
Emulations for CLOCK_REALTIME:
Use gettimeofday() defined by SUS. (SUSv4 obsoleted it, though.) The resolution is 1 microsecond.
Use time() defined by ISO C. The resolution is 1 second.
Emulations for CLOCK_MONOTONIC:
Use mach_absolute_time(), available on Darwin. The resolution is CPU dependent.
Use the result value of times() defined by POSIX. POSIX defines it as “times() shall return the elapsed real time, in clock ticks, since an arbitrary point in the past (for example, system start-up time)”. For example, GNU/Linux returns a value based on jiffies and it is monotonic. However, 4.4BSD uses gettimeofday() and it is not monotonic. (FreeBSD uses clock_gettime(CLOCK_MONOTONIC) instead, though.) The resolution is the clock tick. “getconf CLK_TCK” command shows the clock ticks per second. (The clock ticks per second is defined by HZ macro in older systems.) If it is 100 and clock_t is 32 bits integer type, the resolution is 10 millisecond and cannot represent over 497 days.
Emulations for CLOCK_PROCESS_CPUTIME_ID:
Use getrusage() defined by SUS. getrusage() is used with RUSAGE_SELF to obtain the time only for the calling process (excluding the time for child processes). The result is addition of user time (ru_utime) and system time (ru_stime). The resolution is 1 microsecond.
Use times() defined by POSIX. The result is addition of user time (tms_utime) and system time (tms_stime). tms_cutime and tms_cstime are ignored to exclude the time for child processes. The resolution is the clock tick. “getconf CLK_TCK” command shows the clock ticks per second. (The clock ticks per second is defined by HZ macro in older systems.) If it is 100, the resolution is 10 millisecond.
Use clock() defined by ISO C. The resolution is 1/CLOCKS_PER_SEC. CLOCKS_PER_SEC is the C-level macro defined by time.h. SUS defines CLOCKS_PER_SEC is 1000000. Non-Unix systems may define it a different value, though. If CLOCKS_PER_SEC is 1000000 as SUS, the resolution is 1 microsecond. If CLOCKS_PER_SEC is 1000000 and clock_t is 32 bits integer type, it cannot represent over 72 minutes.
If the given clock_id is not supported, Errno::EINVAL is raised.
unit specifies a type of the return value.
number of seconds as a float (default)
number of milliseconds as a float
number of microseconds as a float
number of seconds as an integer
number of milliseconds as an integer
number of microseconds as an integer
number of nanoseconds as an integer
The underlying function, clock_gettime(), returns a number of nanoseconds. Float object (IEEE 754 double) is not enough to represent the return value for CLOCK_REALTIME. If the exact nanoseconds value is required, use :nanoseconds as the unit.
The origin (zero) of the returned value varies. For example, system start up time, process start up time, the Epoch, etc.
The origin in CLOCK_REALTIME is defined as the Epoch (1970-01-01 00:00:00 UTC). But some systems count leap seconds and others doesn’t. So the result can be interpreted differently across systems. Time.now is recommended over CLOCK_REALTIME.
Returns the time resolution returned by POSIX clock_getres() function.
clock_id specifies a kind of clock. See the document of Process.clock_gettime for details.
clock_id can be a symbol as Process.clock_gettime. However the result may not be accurate. For example, +Process.clock_getres(:GETTIMEOFDAY_BASED_CLOCK_REALTIME)+ returns 1.0e-06 which means 1 microsecond, but actual resolution can be more coarse.
If the given clock_id is not supported, Errno::EINVAL is raised.
unit specifies a type of the return value. Process.clock_getres accepts unit as Process.clock_gettime. The default value, :float_second, is also same as Process.clock_gettime.
Process.clock_getres also accepts :hertz as unit. :hertz means a the reciprocal of :float_second.
:hertz can be used to obtain the exact value of the clock ticks per second for times() function and CLOCKS_PER_SEC for clock() function.
+Process.clock_getres(:TIMES_BASED_CLOCK_PROCESS_CPUTIME_ID, :hertz)+ returns the clock ticks per second.
+Process.clock_getres(:CLOCK_BASED_CLOCK_PROCESS_CPUTIME_ID, :hertz)+ returns CLOCKS_PER_SEC.
p Process.clock_getres(Process::CLOCK_MONOTONIC) #=> 1.0e-09
Suggests gems based on the supplied gem_name. Returns an array of alternative gem names.
creates TCP/IP server sockets for host and port. host is optional.
If no block given, it returns an array of listening sockets.
If a block is given, the block is called with the sockets. The value of the block is returned. The socket is closed when this method returns.
If port is 0, actual port number is chosen dynamically. However all sockets in the result has same port number.
# tcp_server_sockets returns two sockets. sockets = Socket.tcp_server_sockets(1296) p sockets #=> [#<Socket:fd 3>, #<Socket:fd 4>] # The sockets contains IPv6 and IPv4 sockets. sockets.each {|s| p s.local_address } #=> #<Addrinfo: [::]:1296 TCP> # #<Addrinfo: 0.0.0.0:1296 TCP> # IPv6 and IPv4 socket has same port number, 53114, even if it is chosen dynamically. sockets = Socket.tcp_server_sockets(0) sockets.each {|s| p s.local_address } #=> #<Addrinfo: [::]:53114 TCP> # #<Addrinfo: 0.0.0.0:53114 TCP> # The block is called with the sockets. Socket.tcp_server_sockets(0) {|sockets| p sockets #=> [#<Socket:fd 3>, #<Socket:fd 4>] }
Creates UDP/IP sockets for a UDP server.
If no block given, it returns an array of sockets.
If a block is given, the block is called with the sockets. The value of the block is returned. The sockets are closed when this method returns.
If port is zero, some port is chosen. But the chosen port is used for the all sockets.
# UDP/IP echo server Socket.udp_server_sockets(0) {|sockets| p sockets.first.local_address.ip_port #=> 32963 Socket.udp_server_loop_on(sockets) {|msg, msg_src| msg_src.reply msg } }
Receive UDP/IP packets from the given sockets. For each packet received, the block is called.
The block receives msg and msg_src. msg is a string which is the payload of the received packet. msg_src is a Socket::UDPSource object which is used for reply.
Socket.udp_server_loop can be implemented using this method as follows.
udp_server_sockets(host, port) {|sockets|
loop {
readable, _, _ = IO.select(sockets)
udp_server_recv(readable) {|msg, msg_src| ... }
}
}
creates a UNIX server socket on path
If no block given, it returns a listening socket.
If a block is given, it is called with the socket and the block value is returned. When the block exits, the socket is closed and the socket file is removed.
socket = Socket.unix_server_socket("/tmp/s") p socket #=> #<Socket:fd 3> p socket.local_address #=> #<Addrinfo: /tmp/s SOCK_STREAM> Socket.unix_server_socket("/tmp/sock") {|s| p s #=> #<Socket:fd 3> p s.local_address #=> # #<Addrinfo: /tmp/sock SOCK_STREAM> }