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:
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)
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 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 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_tbatteries[MAX_ITEMS]
Array for existing batteries, loop until globals->battery_count
fan_tfans[MAX_ITEMS]
Array for existing fans, loop until globals->fan_count
thermal_tthermals[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 documentation in the doc/
directory.
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. :)