libacpi(3) Library Functions Manual libacpi(3)
NAME
libacpi - general purpose library for ACPI
SYNOPSIS
#include <libacpi.h>
DESCRIPTION
The libacpi library routines provide its users a method of reading ACPI values in a comfortable way. This includes battery information, fan
states, thermal zones and AC states.
A program using these routines must be linked with -lacpi option.
To initialize this functionality you have to first allocate space for a global_t structure
global_t *global = malloc (sizeof (global_t));
Now use the check_acpi_support() function to check if the system actually supports ACPI. In case it does the function will return SUCCESS
or NOT_SUPPORTED on failure.
Now you can use the following functions to initialize the values you get from the ACPI interface:
init_acpi_batt(global);
init_acpi_acadapt(global);
init_acpi_fan(global);
init_acpi_thermal(global);
To know if some of the features is not supported it is a good idea to store the return values in some variable.
If you want to read non-static values the ACPI interface provides (for example battery percentage), use the following functions to do this:
read_acpi_batt(int num)
read_acpi_zone(int num, global_t *globals);
read_acpi_fan(int num)
read_acpi_acstate(global_t *globals);
Since you can have more than one battery, fan and thermal zone, num is the number you want to read, for example in a loop.
thermal_t *tp;
....
for(i=0; i<global->thermal_count; i++){
read_acpi_zone(i, global);
tp = &thermals[i];
...
}
Structures
struct fan_t
fan data
struct battery_t
information found about battery
struct thermal_t
information about thermal zone
struct adapter_t
information about ac adapater
struct global_t
global acpi structure
Functions
int init_acpi_batt (global_t *globals)
int init_acpi_acadapt (global_t *globals)
int init_acpi_thermal (global_t *globals)
int init_acpi_fan (global_t *globals)
int check_acpi_support (void)
int read_acpi_batt (const int num)
void read_acpi_acstate (global_t *globals)
int read_acpi_zone (const int num, global_t *globals)
int read_acpi_fan (const int num)
Variables
battery_t batteries [MAX_ITEMS]
thermal_t thermals [MAX_ITEMS]
fan_t fans [MAX_ITEMS]
Enumerations
enum { ITEM_EXCEED = -5, DISABLED = -4, NOT_PRESENT = -3, ALLOC_ERR = -2, NOT_SUPPORTED = -1, SUCCESS }
enum power_state_t { P_AC, P_BATT, P_ERR }
enum thermal_state_t { T_CRIT, T_HOT, T_PASS, T_ACT, T_OK, T_ERR }
enum charge_state_t { C_CHARGE, C_DISCHARGE, C_CHARGED, C_NOINFO, C_ERR }
enum batt_state_t { B_HIGH, B_MED, B_LOW, B_CRIT, B_HARD_CRIT, B_ERR }
enum thermal_mode_t { CO_ACT, CO_PASS, CO_CRIT, CO_ERR }
enum fan_state_t { F_ON, F_OFF, F_ERR }
Detailed Description
Now follows a more detailed description of functions, structures and enums.
Definition in file libacpi.h.
Function Documentation
int check_acpi_support (void)
Checks if the system does support ACPI or not.
Returns:
SUCCESS if the system supports ACPI or, NOT_SUPPORTED.
int init_acpi_acadapt (global_t * globals)
Finds existing ac adapter and fills the adapt (in globa struct) structure with the paths of the important files to parse.
Parameters:
globals pointer to global acpi structure
Returns: SUCCESS if everything is ok, NOT_SUPPORTED if no information can be found, ALLOC_ERR on allocation errors.
int init_acpi_batt (global_t * globals)
Finds existing batteries and fills the corresponding batteries structures with the paths of the important files to parse.
Parameters:
globals pointer to global acpi structure
Returns: SUCCESS if everything is ok, NOT_SUPPORTED if no information can be found, ALLOC_ERR on allocation errors and ITEM_EXCEED if
there are more batteries found than MAX_ITEMS, this should never happen.
int init_acpi_fan (global_t * globals)
Finds existing fans and fills corresponding fan structures with the paths of the important files to parse for fan information.
Parameters:
globals pointer to global acpi structure
Returns: SUCCESS if everything is ok, NOT_SUPPORTED if no information can be found, ALLOC_ERR on allocation errors and ITEM_EXCEED if
there are more fans found than MAX_ITEMS, this should never happen.
int init_acpi_thermal (global_t * globals)
Finds existing thermal zones and fills corresponding thermal structures with the paths of the important files to parse for thermal informa-
tion.
Parameters:
globals pointer to global acpi structure
Returns: SUCCESS if everything is ok, NOT_SUPPORTED if no information can be found, ALLOC_ERR on allocation errors and ITEM_EXCEED if
there are more thermal zones found than MAX_ITEMS, this should never happen.
void read_acpi_acstate (global_t * globals)
Looks up if the ac adapter is plugged in or not and sets the values in a struct
Parameters:
globals pointer to the global acpi structure
Referenced by init_acpi_acadapt().
int read_acpi_batt (const int num)
Gathers all information of a given battery and filling a struct with it.
Parameters:
num number of battery
Returns: SUCCESS if everything is ok or ITEM_EXCEED if there is not battery num.
int read_acpi_fan (const int num)
Gathers all information about given fan and sets the corresponding values in a struct.
Parameters:
num number for the fan to read
Returns: SUCCESS if everything is ok, ITEM_EXCEED if there is not fan num or NOT_SUPPORTED if the values can't be read. This should not
happen if the init function returned SUCCESS if the ACPI implementation.
int read_acpi_zone (const int num, global_t * globals)
Gathers all information of a given thermal zone and sets the corresponding values in a struct.
Parameters:
num zone
globals pointer to global acpi struct, needed if there is just one zone
Returns: SUCCESS if everything is ok, ITEM_EXCEED if there is not thermal zone num or NOT_SUPPORTED if the values can't be read. This
should not happen if the init function returned SUCCESS if the ACPI implementation.
Enumeration Type Documentation
possible function return values
Enumerator:
ITEM_EXCEED
maximum item count reached
DISABLED
features is disabled
NOT_PRESENT
something is not present
ALLOC_ERR
an error occurred while allocating space
NOT_SUPPORTED
a feature is not supported
SUCCESS
everything was fine
enum batt_state_t
Enumerator:
B_HIGH remaining battery life is high
B_MED remaining battery life is medium
B_LOW remaining battery life is low
B_CRIT remaining battery life is critical
B_HARD_CRIT
remaining battery life is hard critical, you have a few minutes to charge
B_ERR some error occurred while reading the battery state
enum charge_state_t
Enumerator:
C_CHARGE
battery is currently charging
C_DISCHARGE
battery is currently discharging
C_CHARGED
battery is charged
C_NOINFO
hardware doesn't give information about the state
C_ERR some error occurred while reading the charge state
enum fan_state_t
fan states
Enumerator:
F_ON fan is on
F_OFF fan is off
F_ERR some error occurred with this fan
enum power_state_t
Enumerator:
P_AC if computer runs on AC
P_BATT if computer runs on battery
P_ERR no information can be found
enum thermal_mode_t
Enumerator:
CO_ACT fans will be turned after the temperature passes a critical point
CO_PASS
devices will be put in a lower power state after a critical point
CO_CRIT
system goes into suspend to disk if possible after a critical temperature
CO_ERR some error occurred while reading the cooling mode
enum thermal_state_t
Enumerator:
T_CRIT zone reports critical temperature, will cause system to go to S4
T_HOT zone reports high temperature, will cause system to shutdown immediately
T_PASS zone is on passive cooling
T_ACT zone is on active cooling, more power consumption
T_OK zone is ok
T_ERR some error occurred while reading the state of the zone
Variable Documentation
battery_t batteries[MAX_ITEMS]
Array for existing batteries, loop until globals->battery_count
fan_t fans[MAX_ITEMS]
Array for existing fans, loop until globals->fan_count
thermal_t thermals[MAX_ITEMS]
Array for existing thermal zones, loop until globals->thermal_count
Additional information
The package ships a test-libacpi.c file which should be pretty self explanatory. Also have a look into libacpi.h file and the doxygen doc-
umentation in the doc/ directory.
Homepage
See http://www.ngolde.de/libacpi.html
Author
Write to nico (at) ngolde (dot) de for suggestions, hardware donations (very welcome, my notebook doesn't support all features and I could
need a second battery), questions, fixes, bug reports, thanks, etc. :)
LIBACPI libacpi(3)