Error on trying to run a simple RPC program

There is a bug/feature in recent Linux releases of rpcbind - it is now not active/running after system boot, but should somehow be "socket activated" according to systemctl configuration rpcbind.service file in /usr/lib/systemd/system/:

[Install] 
Also=rpcbind.socket

Check this thread on same bug/feature caused Ubuntu issues (https://bugs.launchpad.net/ubuntu/+source/rpcbind/+bug/1558196).

The short answer to yours (ours) issue with rpcbind is - in order to run the RPC server code, do this amendment to systemctrl configuration of your system:

sudo systemctl add-wants multi-user.target rpcbind

Now, the intended way to set rpcbind running is to somehow access /var/run/rpcbind.sock, I would owe much to some Unix/Linux guru that may enlighten me on what RPC server application code shall do in order to achieve this rpcbind "socket activation" effect.

Check whether the service is running using rpcinfo. Here's what I get.

$ rpcinfo 
   program version netid     address                service    owner
    100000    4    tcp6      ::.0.111               portmapper superuser
    100000    3    tcp6      ::.0.111               portmapper superuser
    100000    4    udp6      ::.0.111               portmapper superuser
    100000    3    udp6      ::.0.111               portmapper superuser
    100000    4    tcp       0.0.0.0.0.111          portmapper superuser
    100000    3    tcp       0.0.0.0.0.111          portmapper superuser
    100000    2    tcp       0.0.0.0.0.111          portmapper superuser
    100000    4    udp       0.0.0.0.0.111          portmapper superuser
    100000    3    udp       0.0.0.0.0.111          portmapper superuser
    100000    2    udp       0.0.0.0.0.111          portmapper superuser
    100000    4    local     /run/rpcbind.sock      portmapper superuser
    100000    3    local     /run/rpcbind.sock      portmapper superuser
        24    5    udp       0.0.0.0.3.99           -          superuser
        24    5    tcp       0.0.0.0.3.100          -          superuser

If the service is not running, you have to start it with rpcbind. On Ubuntu I needed root privileges to run the service.

How to install rpcgen

Type this command on the terminal.

sudo apt-get install rpcbind

but at sometimes the above code won't help you to install rpcgen.

At that time you have to follow these steps.Then you can easily install it. you should follow this step by step

sudo apt-get update  
sudo apt-get install rpcbind

Finally you can check it by using this command rpcinfo

First you check that portmapper is working or not, use rpcinfo to check it. If you get any error then install portmap