But in program, its not bad. If I ever need multiple calls to it in same thread:
static char buf[8][32];
static int z;
char *p=buf[z];
z=(z+1)&7;
Static foremost means that the value is preserved from the last function invocation. This is very different behaviour, than an automatically allocated variable. So calling a function with a static variable isn't idempotent, even when all global variables are the same.
> If I ever need multiple calls to it in same thread:
What is this code supposed to do???? It hands out a different pointer, the first 8 times, than starts from the beginning again? I don't see what this is useful for!
What application is that for? Embedded, GUI program, server, ...?
Yes, you should never ever use it in Library.. But small utility functions should be okish :)
This is example from my Ruby graph library. GetMouseEvent can be called alot, but I need at most 2 results. Its Ruby, so I can either dynamicaly allocate objects and let GC pickup them later, or just use static stuff here, no GC overhead. it can be called 100s of times per second, so its worth it.
static GrMouseEvent evs[8];
static int z=0;
GrMouseEvent *ev=&evs[z];