Initial thread is special, cannot pthread_exit()

The initial thread in an i5/OS process is special because of these characteristics:

• If the initial thread calls pthread_exit(), the process terminates.
• If the initial thread is the target of a pthread_cancel() request that is acted upon, the process terminates.
• If the initial thread terminates through any other action, the process terminates.
• Many i5/OS APIs and commands target jobs. Some of those APIs target resources that are allocated to threads for retrieval or modification. If this is the case, the resources that displayed, modified, or retrieved may be the resources owned by the initial thread.

  For example, the CL command WRKACTJOB allows you to display information such as the call stack for a job. Since a job does not have a call stack and the call stack is thread scoped, the call stack of the initial thread is displayed when you choose to display the call stack of a job.

  Other APIs or CL commands that operate against jobs have undergone similar changes. See the specific documentation for the API or CL command of concern.