如何以编程方式阻止Mac进入睡眠状态？

Question

有没有办法阻止Mac以编程方式使用Objective-C进入睡眠状态？苹果开发者网站上的I/O工具包基础部分告诉我，驱动程序会收到空闲/系统睡眠的通知，但是我找不到防止系统进入睡眠状态的方法。它甚至有可能吗？

我遇到过一些其他的解决方案，使用咖啡因，jiggler，失眠，甚至是AppleScript，但我想在Objective-C中做到这一点。谢谢。

Answer 1

只需创建一个触发的功能与此

UpdateSystemActivity(OverallAct); 

我敢肯定，这正是咖啡因做一个NSTimer。

Answer 2

这是苹果官方文件（包括代码片段）：
Technical Q&A QA1340 - How to I prevent sleep?

报价：在Mac OS X防止使用I/O Kit的睡眠10.6雪豹：

#import <IOKit/pwr_mgt/IOPMLib.h> 

// kIOPMAssertionTypeNoDisplaySleep prevents display sleep, 
// kIOPMAssertionTypeNoIdleSleep prevents idle sleep 

// reasonForActivity is a descriptive string used by the system whenever it needs 
// to tell the user why the system is not sleeping. For example, 
// "Mail Compacting Mailboxes" would be a useful string. 

// NOTE: IOPMAssertionCreateWithName limits the string to 128 characters. 
CFStringRef* reasonForActivity= CFSTR("Describe Activity Type"); 

IOPMAssertionID assertionID; 
IOReturn success = IOPMAssertionCreateWithName(kIOPMAssertionTypeNoDisplaySleep, 
            kIOPMAssertionLevelOn, reasonForActivity, &assertionID); 
if (success == kIOReturnSuccess) 
{ 
    // Add the work you need to do without 
    // the system sleeping here. 

    success = IOPMAssertionRelease(assertionID); 
    // The system will be able to sleep again. 
} 

对于较旧的OSX版本，请检查以下内容：
Technical Q&A QA1160 - How can I prevent system sleep while my application is running?

报价：UpdateSystemActivity的用法示例（用于< 10.6规范的方式）

#include <CoreServices/CoreServices.h> 

void 
MyTimerCallback(CFRunLoopTimerRef timer, void *info) 
{ 
    UpdateSystemActivity(OverallAct); 
} 


int 
main (int argc, const char * argv[]) 
{ 
    CFRunLoopTimerRef timer; 
    CFRunLoopTimerContext context = { 0, NULL, NULL, NULL, NULL }; 

    timer = CFRunLoopTimerCreate(NULL, CFAbsoluteTimeGetCurrent(), 30, 0, 0, MyTimerCallback, &context); 
    if (timer != NULL) { 
     CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, kCFRunLoopCommonModes); 
    } 

    /* Start the run loop to receive timer callbacks. You don't need to 
    call this if you already have a Carbon or Cocoa EventLoop running. */ 
    CFRunLoopRun(); 

    CFRunLoopTimerInvalidate(timer); 
    CFRelease(timer); 

    return (0); 
} 

Answer 3

苹果Q&A1340代替Q & A1160。最新Q & A回答了问题“问：当计算机要睡觉或从睡梦中醒来时，我的应用程序如何得到通知？如何防止睡眠？

上市Q&A1340 2：

#import <IOKit/pwr_mgt/IOPMLib.h> 

// kIOPMAssertionTypeNoDisplaySleep prevents display sleep, 
// kIOPMAssertionTypeNoIdleSleep prevents idle sleep 

//reasonForActivity is a descriptive string used by the system whenever it needs 
// to tell the user why the system is not sleeping. For example, 
// "Mail Compacting Mailboxes" would be a useful string. 

// NOTE: IOPMAssertionCreateWithName limits the string to 128 characters. 
CFStringRef* reasonForActivity= CFSTR("Describe Activity Type"); 

IOPMAssertionID assertionID; 
IOReturn success = IOPMAssertionCreateWithName(kIOPMAssertionTypeNoDisplaySleep, 
            kIOPMAssertionLevelOn, reasonForActivity, &assertionID); 
if (success == kIOReturnSuccess) 
{ 

    //Add the work you need to do without 
    // the system sleeping here. 

    success = IOPMAssertionRelease(assertionID); 
    //The system will be able to sleep again. 
} 

请注意，您只能停止空闲时间睡觉，睡不着由用户触发。

对于支持Mac OS X 10.6及更高版本的应用程序，请使用新的IOPMAssertion系列函数。这些功能允许其他应用程序和实用程序查看您的应用程序不想睡觉的愿望;这对于与第三方电源管理软件无缝配合非常重要。