linux man page for btop

btop(9F)						   Kernel Functions for Drivers 						  btop(9F)

NAME
       btop - convert size in bytes to size in pages (round down)

SYNOPSIS
       #include <sys/ddi.h>

       unsigned long btop(unsigned long numbytes);

INTERFACE LEVEL
       Architecture independent level 1 (DDI/DKI).

PARAMETERS
       numbytes        Number of bytes.

DESCRIPTION
       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.

RETURN VALUES
       The return value is always the number of pages. There are no invalid input values, and therefore no error return values.

CONTEXT
       btop() can be called from user or interrupt context.

SEE ALSO
       btopr(9F), ddi_btop(9F), ptob(9F)

       Writing Device Drivers

SunOS 5.10							    11 Apr 1991 							  btop(9F)