Technical Reference: Base Operating System and Extensions, Volume 1

pmlib_request_battery Subroutine

Purpose

Queries and controls the battery status.

Library

PM (Power Management) Library (libpm.a)

Syntax

#include <pmlib.h>

int pmlib_request_battery (cmd, pmb);
int cmd;
pmlib_battery_t *pmb;

Parameters

cmd

Determines the action to be taken by the pmlib_request_battery subroutine and is one of the following values:

PMLIB_QUERY_BATTERY: Queries the battery state.
PMLIB_DISCHARGE_BATTERY: Discharges the battery.

pmb

Points to the following pmlib_battery_t structure:

typedef struct _pmlib_battery {
   int attribute;          /*battery attribute*/
   int capacity;           /*battery capacity*/
   int remain;             /*current remain capacity*/
   int refresh_discharge_capacity;
   int refresh_discharge_time; /*discharge time*/
   int full_change_count;
} pmlib_battery_t;

When cmd is PMLIB_QUERY_BATTERY, the returned pmb.attribute is bit-wise OR of following values:

PMLIB_BATTERY_SUPPORTED	Battery is supported.
PMLIB_BATTERY_EXIST	Battery exists.
PMLIB_BATTERY_NICD	Battery is NiCd
PMLIB_BATTERY_CHARGING	Battery is being charged.
PMLIB_BATTERY_DISCHARGING	Battery is being discharged.
PMLIB_BATTERY_AC	AC adapter is in use.
PMLIB_BATTERY_DC	Battery is in use.
PMLIB_BATTERY_REFRESH_REQ	Need to refresh battery.

Description

The pmlib_request_battery subroutine queries the battery information or requests to discharge the battery. The pmlib_request_ subroutine can be called by any user.

Return Values

Upon successful completion, PMLIB_SUCCESS is returned. If the pmlib_request_state subroutine fails, PMLIB_ERROR is returned and errno variable is set to an error code.

Error Codes

ESRCH	PM daemon is not running.
EINVAL	Invalid argument.

Implementation Specifics

The pmlib_request_battery subroutine is part of the Base Operation System (BOS) Runtime.

Related Information

The pmlib_get_event_notice (pmlib_get_event_notice Subroutine) subroutine, pmlib_request_state (pmlib_request_state Subroutine) subroutine, pmlib_request_parameter (pmlib_request_parameter Subroutine) subroutine, pmlib_register_application (pmlib_register_application Subroutine) subroutine.