dtoc(9) [netbsd man page]

CTOD(9) 						   BSD Kernel Developer's Manual						   CTOD(9)

NAME

     ctod -- macros related to bytes, pages, and disk blocks

SYNOPSIS

     #include <sys/param.h>

     size
     ctod(size x);

     size
     dtoc(size x);

     size
     ctob(size x);

     size
     btoc(size x);

     size
     dbtob(size x);

     size
     btodb(size x);

DESCRIPTION

     The ctod family of macros can be used to convert between bytes, pages (``clicks''), and disk blocks.

     The following table lists the possible conversions:

	   Macro	   From 	   To
	   ctod()	   pages	   disk blocks
	   dtoc()	   disk blocks	   pages
	   ctob()	   pages	   bytes
	   btoc()	   bytes	   pages
	   dbtob()	   disk blocks	   bytes
	   btodb()	   bytes	   disk blocks

     These are typical macros that may appear with different names in other operating systems.	Examples include btop() and btopr() in Solaris.

SEE ALSO

     param(3)

HISTORY

     Some of these macros appeared in Version 7 AT&T UNIX.

CAVEATS

     The described macros make no assumptions about the type of the input parameter.  A caller should ensure that neither integer overflow nor
     integer underflow are possible.

BSD
								   April 8, 2011							       BSD

PARAM(3)						   BSD Library Functions Manual 						  PARAM(3)

NAME

     param -- common parameters

SYNOPSIS

     #include <sys/param.h>

     size
     MAX(size a, size b);

     size
     MIN(size a, size b);

DESCRIPTION

     The <sys/param.h> header includes some common definitions and macros specific to NetBSD.  The header is perhaps best characterized as a ker-
     nel equivalent of <sys/types.h>.  The following list summarizes the provided definitions and macros.

	   o   First and foremost, the header defines the version of NetBSD.  This is defined as

		     #define __NetBSD_Version__    599004800   /* 5.99.48 */

	       The general format is ``MMmmrrpp00'', where 'MM' and 'mm' denote the major and minor version, respectively, 'rr' is provided for
	       compatibility, and 'pp' defines the patch level.

	   o   Common utility macros such as MAX() and MIN() as well as more specific macros such as STACK(9), ctod(9), mstohz(9), roundup(9), and
	       setbit(9).

	   o   Numerous miscellaneous definitions such as limits, constants for the kernel memoryallocators(9), scale factors used by the sched-
	       uler, kthread(9) priorities, and many others.

	   o   Definitions provided for historical and compatibility reasons.  Examples range from definitions such as ``#define BSD'' to old pri-
	       ority levels used in the kernel.

SEE ALSO

     bitops(3), cdefs(3), types(3), unistd(3)

HISTORY

     A <param.h> header appeared already in the Version 4 AT&T UNIX.

BSD
								  April 10, 2011							       BSD