memccpy, memchr, memcmp, memcpy, memmove, memset - Perform
memory operations
#include <string.h>
void *memccpy(
void *s1,
const void *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 ); int *memcpy(
void *s1,
const void *s2,
size_t n ); int *memmove(
void *s1,
const void *s2,
size_t n ); int *memset(
void *s,
int c,
size_t n );
Standard C Library (libc)
Interfaces documented on this reference page conform to
industry standards as follows:
memchr(), memcmp(), memcpy(), memmove(), memset(): ISO C,
XPG4, XPG4-UNIX
memccpy(): XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Points to the location of a string. Points to the location
of a destination string. Points to the location of a
source string. Specifies a character for which to search
(except for memset(), in which c is the target of the
copy). Specifies the number of characters to search.
The memccpy(), memchr(), memcmp(), memcpy(), memmove(),
and memset() functions operate on strings in memory areas.
A memory area is a group of contiguous characters bound by
a count and not terminated by a null character. These memory
functions do not check for overflow of the receiving
memory area. All of the functions are declared in the
string.h header file.
The memccpy() function sequentially copies bytes from the
location pointed to by the s2 parameter into the location
pointed to by the s1 parameter until one of the following
occurs: The character specified by the c parameter, which
is converted to an unsigned char, is copied. The number
of characters specified by the n parameter has been copied
to the string at location s1.
The memccpy() function returns a pointer to the character
that follows character c in the string pointed to by s1.
If character c is not encountered after n characters have
been copied to the string at location s1, this function
returns a null pointer.
The memchr() function returns a pointer to the first
occurrence of character (byte) c in the string pointed to
by s. If character c is not encountered after n bytes have
been copied to the string at location s, this function
returns a null pointer.
The memcmp() function compares the first n characters
(bytes), which are converted to unsigned char, of the
string pointed to by the s1 parameter with the first n
characters (also interpreted as unsigned char) of the
string pointed to by the s2 parameter.
The memcmp() function returns 0 (zero) or a nonzero value
to indicate the results of the comparison operation. The
sign of a nonzero value is determined by the sign of the
difference between the values of the first pair of bytes
that differ in the strings being compared. Possible return
values and their meanings follow: When s1 is less than s2
When s1 is equal to s2 When s1 is greater than s2
The memcpy() function copies n bytes from the string
pointed to by the s2 parameter into the location pointed
to by the s1 parameter. When copying overlapping strings,
the behavior of this function is unreliable.
The memmove() function copies n bytes from the string at
the location pointed to by the s2 parameter to the string
at the location pointed to by the s1 parameter. Copying
takes place as though the n number of bytes from string s2
were first copied into a temporary location having n bytes
that do not overlap either of the strings pointed to by s1
and s2. Then, n number of bytes from the temporary location
is copied to the string pointed to by s1. Consequently,
this operation is nondestructive and proceeds
from left to right.
The memset() function copies the value of the byte specified
by the c parameter, which is converted to an unsigned
char, into each of the first n locations of the string
pointed to by the s parameter.
The memccpy() function returns a pointer to the byte following
the character (byte) specified by the c parameter
in the string pointed to by the s1 parameter. If character
c is not found after the number of bytes specified by the
n parameter are scanned, the function returns a null
pointer.
The memchr() function returns a pointer to the character
(byte) specified by the c parameter. If character c does
not occur after n bytes in the string pointed to by the s
parameter are scanned, the function returns a null
pointer.
The memcmp() function returns a value greater than, equal
to, or less than 0 (zero), according to whether the string
pointed to by the s1 parameter has a value greater than,
equal to, or less than the string pointed to by the s2
parameter.
The memcpy() and memmove() functions return the string
pointed to by the s1 parameter. No return value is
reserved to indicate an error.
The memset() function returns the string pointed to by the
s parameter.
Functions: bcopy(3), string(3), swab(3), wmemcpy(3)
Standards: standards(5)
memccpy(3)
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