If the library fails, then make sure that the port mapper is working correctly. The function of the port mapper is to determine a unique port number on which the client can send and the server can listen. The typical way this is done is that the server registers itself with the port mapper with a program number and version number. (In this library, these are the defined macros PROG_NO and PROG_VER in the graphics.h file).The client also knows both the PROG_NO and PROG_VER and contacts the portmapper on the server with this information. The port mapper then responds with a unique port number. This unique port number is then used by the client (clients) to send and listen.

In some cases a user may need to bypass the portmapper. This usually happens in cases where the setup is not correct. In these instances, the portmapper on the host can be bypassed and the user can supply the port number. Please refer to the description of the G_InitGraphicsNode on the client side of the library to find out exactly how this is done. One easy way to accomplish this is to supply the port number as reported by the compute process.

Whenever the user needs to supply a port number, it may be found using the rpcinfo command. In the output of the rpcinfo command check for the entry which has the same entry for the PROG_NO and PROG_VER. The corresponding entry in the port number is the requisite value. An easier way to do this would be to just observe the port number which the server process prints to the standard output as the application is launched.

If the previous discussion sounds somewhat complicated, most likely the user will not have to worry about it. This information is needed only if Portmapper is present on the server, but still the library fails.

If G3D is used to remotely execute the process, then the port number is directly taken from the standard output. The user is not required to supply the port number in this case.

NOTE FOR LINUX USERS

If you are a linux user using dial-up modem and slirp, always keep the port number. While running G3D, before selecting the connect button, change the port number entry in the dialog box to 0.