#include <unistd.h>
int
getpagesize(void);
The getpagesize() function returns the number of bytes in a page. Page
granularity is the granularity of many of the memory management calls.
The page size is a system page size and may not be the same as the under-
lying hardware page size.
pagesize(1), sbrk(2)
The getpagesize() function appeared in 4.2BSD.
BSD June 4, 1993 BSD