[Mpi3-tools] MPIT_CTRLVAR_WRITE return codes

[Andreas Kuntze]

Hi all,

in the current draft, MPIT_CTRLVAR_WRITE can return the error codes 
PIT_ERR_SETNOTNOW and PIT_ERR_SETNEVER only. For my implementation it would be 
useful, if you could return something indicating that the value you want to 
write is out of range or that not all elements could be changed (if a control 
variable contains more than one element). 

Andreas