MEMORY(2) MEMORY(2)
NAME
memccpy, memchr, memcmp, memcpy, memmove, memset - memory
operations
SYNOPSIS
#include <u.h>
#include <libc.h>
void* memccpy(void *s1, void *s2, int c, ulong n)
void* memchr(void *s, int c, ulong n)
int memcmp(void *s1, void *s2, ulong n)
void* memcpy(void *s1, void *s2, ulong n)
void* memmove(void *s1, void *s2, ulong n)
void* memset(void *s, int c, ulong n)
DESCRIPTION
These functions operate efficiently on memory areas (arrays
of bytes bounded by a count, not terminated by a zero byte).
They do not check for the overflow of any receiving memory
area.
Memccpy copies bytes from memory area s2 into s1, stopping
after the first occurrence of byte c has been copied, or
after n bytes have been copied, whichever comes first. It
returns a pointer to the byte after the copy of c in s1, or
zero if c was not found in the first n bytes of s2.
Memchr returns a pointer to the first occurrence of byte c
in the first n bytes of memory area s, or zero if c does not
occur.
Memcmp compares its arguments, looking at the first n bytes
only, and returns an integer less than, equal to, or greater
than 0, according as s1 is lexicographically less than,
equal to, or greater than s2. The comparison is bytewise
unsigned.
Memcpy copies n bytes from memory area s2 to s1. It returns
s1.
Memmove works like memcpy, except that it is guaranteed to
work if s1 and s2 overlap.
Memset sets the first n bytes in memory area s to the value
of byte c. It returns s.
Page 1 Plan 9 (printed 12/22/24)
MEMORY(2) MEMORY(2)
SOURCE
All these routines have portable C implementations in
/sys/src/libc/port. Most also have machine-dependent assem-
bly language implementations in /sys/src/libc/$objtype.
SEE ALSO
strcat(2)
BUGS
ANSI C does not require memcpy to handle overlapping source
and destination; on Plan 9, it does, so memmove and memcpy
behave identically.
If memcpy and memmove are handed a negative count, they
abort.
Page 2 Plan 9 (printed 12/22/24)