On Wed, 22 Mar 2023, NeilBrown wrote: > On Wed, 22 Mar 2023, Xiao Ni wrote: > > > > > Second, are there possibilities that the arguments "dev" and "name" of > > function create_mddev > > are null at the same time? > > No. For Build or Create, dev is never NULL. For Assemble and > Incremental, name is never NULL. > I should clarify this a bit. For Assemble and Incremental, "name" is never NULL *but* it might be an empty string. So: if (name && name[0] == 0) name = NULL; might cause it to become NULL. So you cannot assume there is always either a valid "dev" or a valid "name". "dev" might be NULL, and "name" might be "". NeilBrown