svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
memcmp(3c)
memory(3C) Standard C Library Functions memory(3C)
NAME
memory, memccpy, memchr, memcmp, memcpy, memmove, memset, explicit_mem‐
set, memmem, memcpy_s, memmove_s, memset_s - 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);
void *explicit_memset(void *s, int c, size_t n);
void *memmem(const void *haystack, size_t haystacklen,
const void *needle, size_t needlelen);
C11 Bounds Checking Interfaces
#define __STDC_WANT_LIB_EXT1__ 1
#include <string.h>
errno_t memcpy_s(void *restrict s1, rsize_t s1max,
const void *restrict s2, rsize_t n);
errno_t memmove_s(void *s1, rsize_t s1max,
const void *s2, rsize_t n);
errno_t memset_s(void *s, rsize_t smax, int c, rsize_t n);
ISO C++
#include <string.h>
const void *memchr(const void *s, int c, size_t n);
#include <cstring>
void *std::memchr(void *s, int c, size_t n);
DESCRIPTION
These functions operate as efficiently as possible on memory areas (ar‐
rays of bytes bounded by a count, not terminated by a null character).
They do not check for the overflow of any receiving memory area. Except
for the C11 Bounds Checking Interfaces, they do not check for null
pointers, and programs may crash if passing null or otherwise invalid
pointers to these functions. Use of adi(7) may help in detecting in‐
valid pointer usage in code.
The memccpy() function copies bytes from memory area s2 into s1, stop‐
ping 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. If copying
takes place between objects that overlap, the behavior is undefined.
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 to whether s1 is lex‐
icographically less than, equal to, or greater than s2 when taken to be
unsigned characters. The execution time of the memcmp() function may
depend on the sequences being compared. For uses such as cryptography
where invariant timing is desired, see timingsafe_memcmp(3C) instead.
The memcpy() function copies n bytes from memory area s2 to s1. It re‐
turns s1. If copying takes place between objects that overlap, the be‐
havior is undefined - the memmove() function should be used instead for
overlapping copies.
The memmove() function copies n bytes from memory area s2 to memory
area s1. Copying between objects that overlap will take place cor‐
rectly. 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.
The explicit_memset() function performs the same operation as memset().
It differs from memset() in that it will not be removed by compiler
dead store analysis. The explicit_memset() function is useful for
clearing no longer needed sensitive data to ensure that it does not re‐
main accessible in process memory.
The memmem() function locates the start of the first occurrence of the
substring needle of length needlelen in the memory area haystack of
length haystacklen. It returns a pointer to the start of the substring,
or NULL if the substring is not found. If needlelen is zero, haystack
is returned. If haystacklen is less than needlelen, NULL is returned.
C11 Bounds Checking Interfaces
The memcpy_s(), memmove_s(), and memset_s() functions are part of the
C11 bounds checking interfaces specified in the C11 standard, Annex K.
Each provide equivalent functionality to the respective memcpy(), mem‐
move(), and memset() functions, except with differing parameters and
return type in order to provide explicit runtime-constraints as defined
in the C11 standard. See runtime_constraint_handler(3C) and IN‐
CITS/ISO/IEC 9899:2011.
If no runtime-constraint violation is detected, the memcpy_s(), mem‐
move_s(), and memset_s() functions return zero. If a runtime constraint
violation is detected and the handler returns, they return a non-zero
value.
ERRORS
No errors are defined for the memccpy(), memchr(), memcmp(), memcpy(),
memmove(), memset(), explicit_memset(), or memmem() functions. The be‐
havior of these functions is undefined if null or invalid pointers are
passed for any of their pointer arguments.
The memcpy_s() function will fail if:
EINVAL NULL pointer passed or source and destination overlap.
ERANGE size argument is invalid, that is, s1max or n is greater than
RSIZE_MAX or n is greater than s1max.
The memmove_s() function will fail if:
EINVAL NULL pointer passed.
ERANGE size argument is invalid, that is, s1max or n is greater than
RSIZE_MAX or n is greater than s1max.
The memset_s() function will fail if:
EINVAL NULL pointer passed.
ERANGE size argument is invalid, that is, smax or n is greater than
RSIZE_MAX or n is greater than smax.
USAGE
Using memcpy() might be faster than using memmove() if the application
knows that the objects being copied do not overlap.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
TRIBUTE VALUE _ Interface StabilityCommitted _ MT-LevelSee below _
StandardSee below
MT-Level
The memccpy(), memchr(), memcmp(), memcpy(), memmove(), memset(), ex‐
plicit_memset(), and memmem() functions are Async-Signal-Safe.
The memcpy_s(), memmove_s(), and memset_s() functions cannot be used
safely in a multithreaded application due to the runtime constraint
handler. For more information, see the runtime_constraint_handler(3C)
man page.
Standard
See standards(7) for descriptions of the following standards:
tab() box; cw(2.2i) |cw(3.3i) lw(2.2i) |lw(3.3i) INTERFACESAPPLICABLE
STANDARDS _ T{ memchr(), memcmp(), memcpy(), memset() T}T{
C89 through C11,
POSIX.1-1990 through 2008,
SUS through SUSv4,
XPG1 through XPG7
T} _ memmove()T{
C89 through C11,
POSIX.1-1990 through 2008,
SUS through SUSv4,
XPG4 through XPG7
T} _ memccpy()T{
POSIX.1-2001 through 2008,
SUS through SUSv4,
XPG1 through XPG7
T} _ T{ memcpy_s(), memmove_s(), memset_s() T}C11 Annex K _
explicit_memset(), memmem()None
SEE ALSO
freezero(3C), string(3C), timingsafe_memcmp(3C), wmemchr(3C), wmem‐
cmp(3C), wmemcpy(3C), wmemmove(3C), wmemset(3C), attributes(7), stan‐
dards(7), runtime_constraint_handler(3C)
NOTES
Overlap between objects being copied can arise even when their (vir‐
tual) 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.
HISTORY
The explicit_memset() function was added to Oracle Solaris in the So‐
laris 11.4.12 release.
The memcpy_s(), memmove_s(), and memset_s() functions were added to Or‐
acle Solaris in the Solaris 11.4.0 release.
The memmem() function was added to Oracle Solaris in the Solaris 11.0.0
release.
The memccpy(), memchr(), memcmp(), memcpy(), memmove(), annd memset()
functions have been included in Solaris since the Solaris 2.0 release.
Oracle Solaris 11.4 2 Jun 2022 memory(3C)