Standard C Library Functions memory(3C)
NAME
memory, memccpy, memchr, memcmp, memcpy, memmove, memset -
memory operations
SYNOPSIS
#include
void *memccpy(void *restrict s1, const void *restrict s2,
int c, sizet n);
void *memchr(const void *s, int c, sizet n);
int memcmp(const void *s1, const void *s2, sizet n);
void *memcpy(void *restrict s1, const void *restrict s2, sizet n);
void *memmove(void *s1, const void *s2, sizet n);
void *memset(void *s, int c, sizet n);
ISO C]
#include
const void *memchr(const void *s, int c, sizet n);
#include
void *std::memchr(void *s, int c, sizet n);
DESCRIPTION
These functions operate as efficiently as possible on memory
areas (arrays of bytes bounded by a count, not terminated by
a null character). They do not check for the overflow of any
receiving memory area.
The memccpy() function copies bytes from memory area s2 into
s1, stopping after the first occurrence of c (converted to
an unsigned char) 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 a null pointer if c
was not found in the first n bytes of s2.
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Standard C Library Functions memory(3C)
The memchr() function returns a pointer to the first
occurrence of c (converted to an unsigned char) in the first
n bytes (each interpreted as an unsigned char) of memory
area s, or a null pointer if c does not occur.
The memcmp() function compares its arguments, looking at the
first n bytes (each interpreted as an unsigned char), 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 when taken to be unsigned characters.
The memcpy() function copies n bytes from memory area s2 to
s1. It returns s1. If copying takes place between objects
that overlap, the behavior is undefined.
The memmove() function copies n bytes from memory area s2 to
memory area s1. Copying between objects that overlap will
take place correctly. It returns s1.
The memset() function sets the first n bytes in memory area
s to the value of c (converted to an unsigned char). It
returns s.
USAGE
Using memcpy() might be faster than using memmove() if the
application knows that the objects being copied do not over-
lap.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
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Standard C Library Functions memory(3C)
ATRIBUTE TYPE ATRIBUTE VALUE
Interface Stability Stable
MT-Level MT-Safe
Standard See standards(5).
SEE ALSO
string(3C), attributes(5), standards(5)
NOTES
Overlap between objects being copied can arise even when
their (virtual) address ranges appear to be disjoint; for
example, as a result of memory-mapping overlapping portions
of the same underlying file, or of attaching the same shared
memory segment more than once.
SunOS 5.11 Last change: 4 Feb 2009 3
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