问在macOS上，应用程序是否可以禁用/抑制所有本身没有发出的系统音频输出？

EN

是的，您可以请求CoreAudio为您提供对音频输出设备的独占访问。这就是所谓的霸占装置。如果您占用了所有的设备，其他应用程序(包括系统)将无法发出任何声音。

像这样的东西对于单个设备来说是很有用的：

AudioObjectPropertyAddress HOG_MODE_PROPERTY = { kAudioDevicePropertyHogMode, kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMaster };
AudioDeviceID deviceId = // your audio device ID
pid_t hoggingProcess = -1; // -1 means attempt to acquire exclusive access
UInt32 size = sizeof(pid_t);

AudioObjectSetPropertyData(deviceId, &HOG_MODE_PROPERTY, 0, NULL, size, &hoggingProcess);
assert(hoggingProcess == getpid()); // check that you have exclusive access

Hog模式通过设置一个名为AudioObject的kAudioDevicePropertyHogMode属性来工作。如果设备未被占用，则属性值为-1。如果它被占用，则值是控制过程的进程id。

如果jump to definition on kAudioDevicePropertyHogMode in Xcode，则可以读取hog模式属性的标头文档。这是了解该属性(以及CoreAudio中的任何其他内容)如何工作的最佳方法。

为了完整起见，下面是头文档：

A pid\_t indicating the process that currently owns exclusive access to the AudioDevice or a value of -1 indicating that the device is currently available to all processes. If the AudioDevice is in a non-mixable mode, the HAL will automatically take hog mode on behalf of the first process to start an IOProc. Note that when setting this property, the value passed in is ignored. If another process owns exclusive access, that remains unchanged. If the current process owns exclusive access, it is released and made available to all processes again. If no process has exclusive access (meaning the current value is -1), this process gains ownership of exclusive access. On return, the pid\_t pointed to by inPropertyData will contain the new value of the property.