title: Daemon under linux fails to launch app with execv
body: <p>We have a command and control daemon running under Fedora 16 that provides various services, including starting one of our ancillary applications.  This has been working for us for quite some time.</p>
  
  <p>In fact it still works - on some systems.</p>
  
  <p>The daemon process forks (successfully) and then calls execv().</p>
  
  <p>Setting up on another system to test, I suddenly have a failure, and execv() fails and returns 127.</p>
  
  <p>Both systems are running Fedora 16, although the one with the problem is 3.3.7-1.fc16.x86_64 whereas another where everything works fine is running 3.4.2-1.fc16.x86_64</p>
  
  <p>If I stop the daemon and run it as a stand-alone application, the whole process works fine.</p>
  
  <p>All searching through documentation on execv() and related fails to bring up a 127 error code, my only guess so far is the Linux 'Command not found' error.  Not knowing what it means is making it hard to fix the problem.  </p>
  
  <p>Can anybody tell me what the 127 return code means?</p>
  
  <p>Thanks!</p>