Consider the following scenario. On a Windows Vista-based computer, a Subsystem for UNIX-based Applications (SUA) process forks a child process. Because the SUA process is not required to wait for the child process to be completed, the SUA process sets the value of the SIGCHILD signal to SIG_IGN. In this scenario, the SUA process expects the child process to be cleared when the child process is complete. However, the child process is unexpectedly marked as a zombie process instead.