c - mpiexec: starting program with zero processes -

i want have error message , exit in case -np set 0 on command line. there way this? seems program stops working without starting.

zero number of processes indeed means not start process @ all. how can have output if have no process create it? no process no process. nothing running. if don't run mpiexec @ all.

i don't kind of error message expect see. perhaps want 1 process?

i tested mpiexec coming openmpi on computer starts 1 process if requests -np 0. other implementations might behave differently.