Group Services Programming Guide and Reference

Using the GSAPI: A Group Services client example

This chapter contains listings of the files required by a sample Group Services client (GS client) program called sample_schg.c. It also contains two sample deactivate scripts.

The sample_schg.c program, as a simple GS client, performs the following functions:

• Reads command-line arguments to set various options, including the group name, protocol controls, and timing options
• Initializes itself as a Group Services client
• Joins the group as a provider
• Proposes a group state value change at the interval specified on input
• Continues running until the program is killed (through the kill command or by otherwise sending it a signal).

For details on setting up the environment and starting the program on several nodes, see the comments in the program listing.

The program requires the following files:

• The sample_schg.c sample program contains the main() function, all of the necessary callback functions, and some utility functions for the application.
• The sample_utility.c utility functions contains utility functions that are used by the sample_schg program.
• The sample_utility.h header file contains declarations for the utility functions in the sample_utility.c program.
• The sample_deactive_ksh.sh deactivate script is a deactivate script written as a Korn shell script.
• The sample_deactive_c_prog.c deactivate script is a deactivate script written as a C program.

You can find the sample_schg.c program and its related files online in the PSSP product samples directory, /usr/sbin/rsct/samples/hags. The hags sample directory also contains files related to two other test programs, sample_test.c, which provides an interactive interface to the Group Services subsystem, and Sample_Subscribe.C, which provides a sample C++ language client that subscribes with Group Services for a user-specified group.