#include <pthread.h> int pthread_attr_getguardsize(const pthread_attr_t *restrict attr, size_t *restrict guardsize);
A conforming implementation is permitted to round up the value contained in guardsize to a multiple of the configurable system variable PAGESIZE . See PAGESIZE in sys/mman.h. If an implementation rounds up the value of guardsize to a multiple of PAGESIZE, a call to pthread_attr_getguardsize() that specifies attr stores, in guardsize, the guard size specified in the previous call to pthread_attr_setguardsize().