#include <sys/ddi.h>unsigned long btop(unsigned long numbytes);
Architecture independent level 1 (DDI/DKI).
btop() returns the number of memory pages that are contained in the specified number of bytes, with downward rounding in the case that the byte count is not a page multiple. For example, if the page size is 2048, then btop(4096) returns 2, and btop(4097) returns 2 as well. btop(0) returns 0.
The return value is always the number of pages. There are no invalid input values, and therefore no error return values.
btop() can be called from user or interrupt context.