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cfg_subsys_state(3)
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cfg_subsys_state - determine the state of the named subsystem
#include <cfg.h>
cfg_status_t cfg_subsys_state(
cfg_handle_t *handle,
caddr_t subsys,
unsigned int *state );
Configuration Management Library (libcfg.a)
Structure identifying the means of communication between
your application 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 following flags are
currently defined: CFG_STATE_CONFIGURED,
CFG_STATE_DYNAMIC, and CFG_STATE_LOADED.
Use the cfg_subsys_state() routine to determine the state
of a particular 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
subsystems 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 subsystems 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 section for more
information about using these constants.
Upon successful completion, cfg_subsys_state() returns
CFG_SUCCESS. Other return values indicate that an error
has occurred. For information about handling return values
from routines in the configuration management library,
see libcfg(3).
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 representing 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.
Commands: cfgmgr(8), sysconfig(8)
Routines: cfg_subsys_list(3), libcfg(3)
cfg_subsys_state(3)
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