btop(9f) [linux man page]

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)

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

NAME

       ptob - convert size in pages to size in bytes

SYNOPSIS

       #include <sys/ddi.h>

       unsigned long ptob(unsigned long numpages);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       numpages        Size in number of pages to convert to size in bytes.

DESCRIPTION

       This  function returns the number of bytes that are contained in the specified number of pages. For example, if the page size is 2048, then
       ptob(2) returns	4096. ptob(0) returns  0.

RETURN VALUES

       The return value is always the number of bytes in the specified number of pages. There are no invalid input values, and no checking will be
       performed  for  overflow in the case of a page count whose corresponding byte count cannot be represented by an	unsigned long. Rather, the
       higher order bits will be ignored.

CONTEXT

       ptob() can be called from user or interrupt context.

SEE ALSO

       btop(9F), btopr(9F), ddi_ptob(9F)

       Writing Device Drivers

SunOS 5.10							    11 Apr 1991 							  ptob(9F)