title: com.apple.xpc.launchd.oneshot
body: <p>In an <code>XCTestCase</code> test, I created a <code>NSTask</code> object and set it to run <code>printenv</code>. Then after the <code>NSTask</code> finished, I ran <code>printenv</code> using <code>fork</code> and <code>execv</code>. The output from both was identical except for one environment variable.</p>
  
  <p>NSTask: <code>XPC_SERVICE_NAME=com.apple.xpc.launchd.oneshot.0x10000004.Xcode</code></p>
  
  <p>execv: <code>XPC_SERVICE_NAME=0</code></p>
  
  <p>What is <code>com.apple.xpc.launchd.oneshot</code>?</p>