It sounds reasonable to make the change but it's better to document it. I don't see the change in the change log and I am surprised that my code doesn't work any more. Or maybe handle the single character case specially so that there is no need to change the source code. Another question is that in the newer version, PetscTruth becomes PetscBool. I might need to switch between development version and current released version. But to change the source code back and forth is a headache. Is there any good way to handle this? Why don't do something like #define PetscTruth PetscBool in the petsc.h so that we do not need to change the source code. Any wrong with that approach? Thanks. --------------------------------------------------------------------------------------------------------------------------------------------------------------------- This behavior was changed because we wanted to always make sure that strings obtained were null terminated. When you pass in a string of length 1 there is only room for the null terminator. We could only do the null termination when the the string is larger than one allowing your old code to work. But that is slightly inconsistent handling that case differently. What do you think? You might consider using something like PetscOptionsGetEList() instead of PetscOptionsGetString() also. Barry