Erlang Thursday – c:regs/0

Today’s Erlang Thursday continues looking at the c module, and looks at c:regs/0.

c:regs/0 displays information about the registered processes on the current node, such as process name, process id, the number of reductions performed, and more.

c:regs().
# 
# ** Registered procs on node nonode@nohost **
# Name                  Pid          Initial Call                      Reds Msgs
# application_controlle <0.7.0>      erlang:apply/2                     463    0
# code_server           <0.19.0>     erlang:apply/2                  121202    0
# erl_prim_loader       <0.3.0>      erlang:apply/2                  156994    0
# error_logger          <0.6.0>      gen_event:init_it/6                220    0
# file_server_2         <0.18.0>     file_server:init/1                  92    0
# global_group          <0.17.0>     global_group:init/1                 59    0
# global_name_server    <0.13.0>     global:init/1                       51    0
# inet_db               <0.16.0>     inet_db:init/1                     206    0
# init                  <0.0.0>      otp_ring0:start/2                 3398    0
# kernel_safe_sup       <0.28.0>     supervisor:kernel/1                 58    0
# kernel_sup            <0.11.0>     supervisor:kernel/1              49109    0
# rex                   <0.12.0>     rpc:init/1                          35    0
# standard_error        <0.21.0>     erlang:apply/2                       9    0
# standard_error_sup    <0.20.0>     supervisor_bridge:standar           41    0
# user                  <0.24.0>     group:server/3                      36    0
# user_drv              <0.23.0>     user_drv:server/2                 1219    0
# 
# ** Registered ports on node nonode@nohost **
# Name                  Id              Command
# ok

While this is not quite as nice as what is provided by the observer GUI, this is a useful tool to be able to get an idea what what the processes are, and what they are doing when you are not able to have the observer GUI running.

The c module also contains a function c:nregs/0 which displays information about all processes for all of the nodes that the node it is run from knows about.

node().
# 'foo@127.0.0.1'
nodes().
# ['bar@127.0.0.1']
c:nregs().
# 
# ** Registered procs on node 'foo@127.0.0.1' **
# Name                  Pid          Initial Call                      Reds Msgs
# application_controlle <0.7.0>      erlang:apply/2                     463    0
# auth                  <0.19.0>     auth:init/1                        880    0
# code_server           <0.25.0>     erlang:apply/2                  122302    0
# erl_epmd              <0.18.0>     erl_epmd:init/1                    268    0
# erl_prim_loader       <0.3.0>      erlang:apply/2                  163458    0
# error_logger          <0.6.0>      gen_event:init_it/6                264    0
# file_server_2         <0.24.0>     file_server:init/1                  92    0
# global_group          <0.23.0>     global_group:init/1                 67    0
# global_name_server    <0.13.0>     global:init/1                      339    0
# inet_db               <0.16.0>     inet_db:init/1                     255    0
# init                  <0.0.0>      otp_ring0:start/2                 5405    0
# kernel_safe_sup       <0.34.0>     supervisor:kernel/1                 58    0
# kernel_sup            <0.11.0>     supervisor:kernel/1              57226    0
# net_kernel            <0.20.0>     net_kernel:init/1                  792    0
# net_sup               <0.17.0>     supervisor:erl_distributi          285    0
# rex                   <0.12.0>     rpc:init/1                          35    0
# standard_error        <0.27.0>     erlang:apply/2                       9    0
# standard_error_sup    <0.26.0>     supervisor_bridge:standar           41    0
# user                  <0.30.0>     group:server/3                      36    0
# user_drv              <0.29.0>     user_drv:server/2                 1661    0
# 
# ** Registered ports on node 'foo@127.0.0.1' **
# Name                  Id              Command
# 
# ** Registered procs on node 'bar@127.0.0.1' **
# Name                  Pid          Initial Call                      Reds Msgs
# application_controlle <6108.7.0>   erlang:apply/2                     463    0
# auth                  <6108.19.0>  auth:init/1                        880    0
# code_server           <6108.25.0>  erlang:apply/2                  124588    0
# erl_epmd              <6108.18.0>  erl_epmd:init/1                    268    0
# erl_prim_loader       <6108.3.0>   erlang:apply/2                  164400    0
# error_logger          <6108.6.0>   gen_event:init_it/6                301    0
# file_server_2         <6108.24.0>  file_server:init/1                  92    0
# global_group          <6108.23.0>  global_group:init/1                 67    0
# global_name_server    <6108.13.0>  global:init/1                      341    0
# inet_db               <6108.16.0>  inet_db:init/1                     255    0
# inet_gethost_native   <6108.42.0>  inet_gethost_native:serve           83    0
# inet_gethost_native_s <6108.41.0>  supervisor_bridge:inet_ge           41    0
# init                  <6108.0.0>   otp_ring0:start/2                 5515    0
# kernel_safe_sup       <6108.34.0>  supervisor:kernel/1                127    0
# kernel_sup            <6108.11.0>  supervisor:kernel/1              57226    0
# net_kernel            <6108.20.0>  net_kernel:init/1                  796    0
# net_sup               <6108.17.0>  supervisor:erl_distributi          285    0
# rex                   <6108.12.0>  rpc:init/1                        1302    0
# standard_error        <6108.27.0>  erlang:apply/2                       9    0
# standard_error_sup    <6108.26.0>  supervisor_bridge:standar           41    0
# user                  <6108.30.0>  group:server/3                      36    0
# user_drv              <6108.29.0>  user_drv:server/2                 2801    0
# 
# ** Registered ports on node 'bar@127.0.0.1' **
# Name                  Id              Command
# ok

–Proctor

Leave a Reply

Your email address will not be published. Required fields are marked *