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NAMEmemory: memccpy(), memchr(), memcmp(), memcpy(), memmove(), memset(), bcmp(), bcopy(), bzero(), ffs() — memory operations SYNOPSIS#include <string.h>
void *memccpy(void *__restrict s1, const void *__restrict s2, int c,
size_t n);
void *memchr(const void *s, int c, size_t n);
int memcmp(const void *s1, const void *s2, size_t n);
void *memcpy(void *__restrict s1, const void *__restrict s2, size_t n);
void *memmove(void *s1, const void *s2, size_t n);
void *memset(void *s, int c, size_t n);
#include <strings.h>
int bcmp(const void *s1, const void *s2, size_t n);
void bcopy(const void *s1, void *s2, size_t n);
void bzero(void *s, size_t n);
int ffs(int i); Remarksbcmp(),
bcopy(),
bzero(),
ffs(),
and
<strings.h>
are provided solely for portability of BSD applications,
and are not recommended for new applications
where portability is important.
For portable applications, use
memcmp(),
memmove(),
and
memset(),
respectively.
ffs()
has no portable equivalent. DESCRIPTIONThese functions operate as efficiently as possible on memory areas
(arrays of bytes bounded by a count,
not terminated by a null byte).
They do not check for the overflow of any receiving memory area. Definitions for all these functions, the type
size_t,
and the constant
NULL
are provided in the
<string.h>
header file.
- memccpy()
Copy bytes from the object pointed to by
s2
into the object pointed to by
s1,
stopping after the first occurrence of byte
c
has been copied, or after
n
bytes have been copied, whichever comes first.
If copying takes place between objects that overlap,
the behavior is undefined.
memccpy()
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. - memchr()
Locate the first occurrence of
c
(converted to an
unsigned char)
in the initial
n
bytes (each interpreted as
unsigned char)
of the object pointed to by
s.
memchr()
returns a pointer to the located byte, or a NULL
pointer if the byte does not occur in the object. - memcmp()
Compare the first
n
bytes of the object pointed to by
s1
to the first
n
bytes of the object pointed to by
s2.
memcmp()
returns an integer greater than, equal to, or less than zero,
according to whether the object pointed to by
s1
is greater than, equal to, or less than the object pointed to by
s2.
The sign of a non-zero return value is determined
by the sign of the difference between the values
of the first pair of bytes (both interpreted as
unsigned char)
that differ in the objects being compared. - memcpy()
Copy
n
bytes from the object pointed to by
s2
into the object pointed to by
s1.
If copying takes place between objects that overlap, the behavior is
undefined.
memcpy()
returns the value of
s1. - memmove()
Copy
n
bytes from the object pointed to by
s2
into the object pointed to by
s1.
Copying takes place as if the
n
bytes from the object pointed to by
s2
are first copied into a temporary array of
n
bytes that does not overlap the objects pointed to by
s1
and
s2,
and then the
n
bytes from the temporary array are copied into the object pointed to by
s1.
memmove()
returns the value of
s1. - memset()
Copy the value of
c
(converted to an
unsigned char)
into each of the first
n
bytes of the object pointed to by
s.
memset()
returns the value of
s. - bcopy()
copies
n
bytes from the area pointed to by
s1
to the area pointed to by
s2. - bcmp()
Compare the first
n
bytes of the area pointed to by
s1
with the area pointed to by
s2.
bcmp()
returns zero if they are identical; non-zero otherwise.
Both areas are assumed to be
n
bytes in length. - bzero()
Clear
n
bytes in the area pointed to by
s
by setting them to zero. - ffs()
Find the first bit set
(beginning with the least significant bit)
and return the index of that bit.
Bits are numbered starting at one.
A return value of 0 indicates that
i
is zero.
International Code Set SupportThese functions support only single-byte byte code sets. WARNINGSThe functions defined in
<string.h>
were previously defined in
<memory.h>. FILES/usr/include/string.h STANDARDS CONFORMANCEmemccpy(): AES, SVID2, SVID3, XPG2, XPG3, XPG4 memchr(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, ANSI C memcmp(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, ANSI C memcpy(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, ANSI C memmove(): AES, SVID3, XPG4, ANSI C memset(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, ANSI C
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