V10/man/adm/man3/memory.3

.TH MEMORY 3
.CT 2 mem_man
.SH NAME
memccpy, memchr, memcmp, memcpy, memmove, memset \(mi memory operations
.SH SYNOPSIS
.nf
.B char *memccpy(s1, s2, c, n)
.B char *s1, *s2;
.B int c, n;
.PP
.B char *memchr(s, c, n)
.B char *s;
.B int c, n;
.PP
.B int memcmp(s1, s2, n)
.B char *s1, *s2;
.B int n;
.PP
.B char *memcpy(s1, s2, n)
.B char *s1, *s2;
.B int n;
.PP
.B char *memmove(s1, s2, n)
.B char *s1, *s2;
.B int n;
.PP
.B char *memset(s, c, n)
.B char *s;
.B int c, n;
.fi
.SH DESCRIPTION
These functions operate efficiently on memory areas
(arrays of characters bounded by a count, not terminated by a null character).
They do not check for the overflow of any receiving memory area.
.PP
.I Memccpy
copies characters from memory area
.I s2
into
.IR s1 ,
stopping after the first occurrence of character
.I c
has been copied, or after
.I n
characters have been copied, whichever comes first.
It returns a pointer to the character after
the copy of
.I c
in
.IR s1 ,
or zero if
.I c
was not found in the first
.I n
characters of
.IR s2 .
.PP
.PP
.I Memchr
returns a pointer to the first
occurrence of character
.I c
in the first
.I n
characters of memory area
.IR s,
or zero if
.I c
does not occur.
.PP
.I Memcmp
compares its arguments, looking at the first
.I n
characters only, and returns an integer
less than, equal to, or greater than 0,
according as
.I s1
is lexicographically less than, equal to, or
greater than
.IR s2 .
.PP
.I Memcpy
copies
.I n
characters from memory area 
.I s2
to
.I s1.
It returns
.I s1.
.PP
.I Memmove
is the same as 
.I memcpy,
except it is guaranteed to handle overlapping strings as
if the move had been made to a temporary and then to the destination.
.PP
.I Memset
sets the first
.I n
characters in memory area
.I s
to the value of character
.IR c .
It returns
.IR s .
.SH SEE ALSO
.IR string (3)
.SH BUGS
.I Memcmp
uses native character comparison, which is signed
on some machines, unsigned on others;
thus the sign of the value returned when a
character has its high-order bit set is implementation-dependent.
.br
Thanks to ANSI X3J11 for the 
.IR memcpy/memmove
distinction.