Writing current battery charge to a float value?

I've found examples on the web for this- none of which are for C. Can anyone provide an example of a C program that scans a laptop's battery charge and writes that to a float value? I'm not at all sure how to go about doing this.

Thanks in advance!

How to: Determine Battery Status

That's C++, but beggars can't be picky. Thanks! I'll see what I can do with this. B-)

Originally Posted by Flotonic

That's C++, but beggars can't be picky. Thanks! I'll see what I can do with this. B-)

It is NOT C++... You can do that very easily in standard C....

What it is is a simple windows API call... Like most of them, you provide the requisite struct, call the function and then extract the data you need...

Here's what the GetSystemPowerStatusEx2 function returns...

Code:

typedef struct _SYSTEM_POWER_STATUS_EX2 {
  BYTE ACLineStatus;
  BYTE BatteryFlag;
  BYTE BatteryLifePercent;
  BYTE Reserved1;
  DWORD BatteryLifeTime;
  DWORD BatteryFullLifeTime;
  BYTE Reserved2;
  BYTE BackupBatteryFlag;
  BYTE BackupBatteryLifePercent;
  BYTE Reserved3;
  DWORD BackupBatteryLifeTime;
  DWORD BackupBatteryFullLifeTime;
  DWORD BatteryVoltage;
  DWORD BatteryCurrent;
  DWORD BatteryAverageCurrent;
  DWORD BatteryAverageInterval;
  DWORD BatterymAHourConsumed;
  DWORD BatteryTemperature;
  DWORD BackupBatteryVoltage;
  BYTE BatteryChemistry;
  //  Add any extra information after the BatteryChemistry member.
} SYSTEM_POWER_STATUS_EX2, *PSYSTEM_POWER_STATUS_EX2, *LPSYSTEM_POWER_STATUS_EX2;

In C.... #include <winbase.h> and link with coredll.lib....

Code:

float GetBatteryTime(void)
  { SYSTEM_POWER_STATUS_EX2  Stat;
     if (GetSystemPowerStatusEx2(&Stat,sizeof(Stat),TRUE))
       return (float) Stat.BatteryLifeTime;      
     else 
       return -1;  }  // error message;

Really... it's not that hard.

Ahh. I got confused because most of the sources on Microsoft.com are in non-C languages. Again, thanks! You did a good job breaking it all down.

Originally Posted by Flotonic

Ahh. I got confused because most of the sources on Microsoft.com are in non-C languages. Again, thanks! You did a good job breaking it all down.

90% of the Windows API is written in C .... some of the newer stuff is C++...

GetSystemPowerStatus Function (Windows)
SYSTEM_POWER_STATUS Structure (Windows)

Assuming you're not using Windows Embedded CE...

gg

Originally Posted by Codeplug

GetSystemPowerStatus Function (Windows)
SYSTEM_POWER_STATUS Structure (Windows)

Assuming you're not using Windows Embedded CE...

gg

Yep... that'll probably be better for laptops... Thanks.