cfg_subsys_state(3)cfg_subsys_state(3)NAMEcfg_subsys_state - determine the state of the named subsystem
SYNOPSIS
#include <cfg.h>
cfg_status_t cfg_subsys_state(
cfg_handle_t *handle,
caddr_t subsys,
unsigned int *state );
LIBRARY
Configuration Management Library (libcfg.a)
PARAMETERS
Structure identifying the means of communication between your applica‐
tion and the configuration management server. For local requests, pass
NULL in this parameter. For remote requests, pass the value you receive
when you call the cfg_connect() routine. Specifies the name of the
subsystem for which you are requesting state information. Returns a
collection of bit flags representing the state of the subsystem. The
bit flags are defined in the <sys/sysconfig.h> header file. The follow‐
ing flags are currently defined: CFG_STATE_CONFIGURED,
CFG_STATE_DYNAMIC, and CFG_STATE_LOADED.
DESCRIPTION
Use the cfg_subsys_state() routine to determine the state of a particu‐
lar subsystem. Subsystems can be loaded, loaded and configured, or
unloaded. (Subsystems must be loaded to be configured.) In addition, a
subsystem can be either static (the CFG_STATE_DYNAMIC bit flag is not
set) or dynamic (the CFG_STATE_DYNAMIC bit flag is set). Static subsys‐
tems are linked into the kernel at build time and the only way to add
or remove them from the kernel is to rebuild the kernel. Dynamic sub‐
systems are loadable, meaning that they can be added and removed from
the kernel while the system is running.
The value returned in the state parameter is an integer representation
of a binary value. The bits in the value designate the state of the
subsystem. For example, the least significant bit designates whether
the subsystem is loaded. If this bit is set, the subsystem is loaded.
If the next higher order bit is set, the subsystem is configured. You
can determine the state of a subsystem by using the value returned in
the state parameter in a bitwise AND operation. The <sys/sysconfig.h>
header file defines constants for this purpose. See the EXAMPLES sec‐
tion for more information about using these constants.
RETURN VALUES
Upon successful completion, cfg_subsys_state() returns CFG_SUCCESS.
Other return values indicate that an error has occurred. For informa‐
tion about handling return values from routines in the configuration
management library, see libcfg(3).
EXAMPLES
The following example illustrates the use of the cfg_subsys_state()
library routine:
cfg_status_t retval; cfg_handle_t handle;
unsigned int state;
retval = cfg_subsys_state(&handle, "vfs", &state);
if (retval != CFG_SUCCESS)
print_error(retval); else {
/* Determine whether or not the subsystem is loaded */
/* and configured. Display a message describing the */
/* subsystem state. */
if (state & CFG_STATE_LOADED) {
if (state & CFG_STATE_CONFIGURED)
printf("The subsystem is loaded and configured.\n");
else
printf("The subsystem is loaded but not configured.\n");
else
printf("The subsystem is unloaded.\n");
} }
In this example, the cfg_subsys_state() routine returns a value repre‐
senting the state of the vfs subsystem. The application determines
whether the call to the routine was successful and, if it was, displays
a message describing the state of the subsystem.
SEE ALSO
Commands: cfgmgr(8), sysconfig(8)
Routines: cfg_subsys_list(3), libcfg(3)cfg_subsys_state(3)