Thread: Macro expansion

I came across a code segment in open source, its like

Code:

#define pthread_exit(x)\
do {\
	dbg("[%x] pthread_exit(" #x ")\n", pthread_self());\
	pthread_exit(x);\
} while(0)

does it mean that the macro pthread_exit(x) will be expanded
multiple times (rather indefinite no of times) ...

& also this code internally does not call exit() system call...
I am confused how the exit is working in true sense

plz comment...

thanks...
onebrother