PHP as FastCGI and exit() function

How exactly is exit() function working when in fastcgi mode? does it finish whole instance of php process in开发者_StackOverflow社区 fastcgi pool or just ends current request and return process to te pool?

if the second answer - what causes logs of this kind:

[warn] FastCGI: (dynamic) server "/php.fcgi" (pid 25113) terminated by calling exit with status '0'

??

Please take a look at this post on serverfault.com.