#include <CoreFoundation/CoreFoundation.h>
#include <ApplicationServices/ApplicationServices.h>
#include <IOKit/graphics/IOGraphicsLib.h>
#include <stdlib.h>
#include <stdio.h>
int main(int argc, char * argv[])
{
io_service_t service;
CGError err;
int i;
CGDisplayCount max;
CGDirectDisplayID displayIDs[8];
CFStringRef key;
float value;
err = CGGetOnlineDisplayList(8, displayIDs, &max);
if(err != kCGErrorSuccess)
exit(1);
if(max > 8)
max = 8;
if( argc < 2)
key = CFSTR(kIODisplayBrightnessKey);
else
key = CFStringCreateWithCString( kCFAllocatorDefault, argv[1],
kCFStringEncodingMacRoman );
for(i = 0; i < max; i++ ) {
service = CGDisplayIOServicePort(displayIDs[i]);
err = IODisplayGetFloatParameter(service, kNilOptions, key, &value);
printf("Display %x: IODisplayGetFloatParameter(%d), %f\n", displayIDs[i], err, value);
if( kIOReturnSuccess != err)
continue;
if (argc < 3)
continue;
sscanf( argv[argc - 1], "%f", &value );
err = IODisplaySetFloatParameter(service, kNilOptions, key, value);
printf("IODisplaySetFloatParameter(%d, %f)\n", err, value);
if( kIOReturnSuccess != err)
continue;
}
exit(0);
return(0);
}