POE returns exit status (a return code value between 0 and 255) on the home node which reflects the composite exit status of the user application. The exit status can have various conditions and values and each can have a specific meaning. These are explained in The IBM Parallel Environment for AIX: MPI Programming Guide.
In addition, if the POE job-step function is used, the job control mechanism is the program's exit code. When the task exit code is 0 (zero), or in the range of 2 to 127, the job-step will be continued. If the task exit code is 1 or greater than 127, POE terminates the parallel job, as well as any remaining user programs in the job-step list. Also, any POE infrastructure failure detected (such as failure to open pipes to the child process) will terminate the parallel job as well as any remaining programs in the job-step list.