Turning on/off OS X displays.

osxp.cpp

#include <CoreFoundation/CoreFoundation.h>
#include <IOKit/IOKitLib.h>

#include <iostream>

void set_request_idle(bool request)
{
    io_registry_entry_t entry = IORegistryEntryFromPath(kIOMasterPortDefault,
            "IOService:/IOResources/IODisplayWrangler");
    if (entry == MACH_PORT_NULL) {
        return;
    }

    IORegistryEntrySetCFProperty(entry, CFSTR("IORequestIdle"),
            request ? kCFBooleanTrue : kCFBooleanFalse);

    IOObjectRelease(entry);
}

int main(int argc, const char **argv)
{
    const std::string &command = (argc > 1) ? argv[1] : "";

    if (command == "idle") {
        set_request_idle(true);
    } else if (command == "wake") {
        set_request_idle(false);
    } else {
        std::cerr << "usage: " << argv[0] << " (idle|wake)\n";
        return 1;
    }

    return 0;
}

Compile with:

clang++ -Wall -O3 -framework Foundation -framework IOKit osxp.cpp -o osxp

To turn off:

osxp idle

To turn on:

osxp wake