bstring.3

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3 代码 · 共 87 行

.\" SCCSID: @(#)bstring.3	8.2	1/28/91
.TH bstring 3 
.SH Name
bcopy, bcmp, bzero, ffs \- bit and byte string operations
.SH Syntax
.nf
.B void bcopy(b1, b2, length)
.B char *b1, *b2;
.B int length;
.PP
.B bcmp(b1, b2, length)
.B char *b1, *b2;
.B int length;
.PP
.B void bzero(b1, length)
.B char *b1;
.B int length;
.PP
.B ffs(i)
.B int i;
.fi
.SH Description
.NXR "bstring keyword"
.NXR "bcopy subroutine"
.NXR "bcmp subroutine"
.NXR "bzero subroutine"
.NXR "ffs subroutine"
.NXR "string" "operations on variable-length"
.NXR "bit" "determining setting in byte"
.NXA "strcat subroutine" "bcopy subroutine"
The functions
.PN bcopy ,
.PN bcmp ,
and
.PN bzero
operate on variable length strings of bytes.
They do not check for null bytes as the routines in
.MS string 3  
do.
.PP
The
.PN bcopy
function copies 
.I length
bytes from string
.I b1
to the string
.IR b2 .
.PP
The
.PN bcmp
function
compares byte string
.I b1
against byte string
.IR b2 ,
returning zero if they are identical,
non-zero otherwise.  Both strings are
assumed to be
.I length
bytes long.
.PP
The
.PN bzero
function places
.I length
0 bytes in the string
.IR b1 .
.PP
The
.I ffs
finds the first bit set in the argument passed it and
returns the index of that bit.  Bits are numbered
starting at 1.  A return value of 0 indicates the
value passed is zero.
.SH Restrictions
The
.PN bcmp
and 
.PN bcopy
routines take parameters backwards from
.PN strcmp
and
.PN strcpy .
.SH See Also
.MS memory 3