illumos: manual page: memset.3c

MEMORY(3C) Standard C Library Functions MEMORY(3C)

NAME

memory, memccpy, memchr, memcmp, memcpy, memmem, memmove, memrchr, memset -
memory operations

SYNOPSIS

#include <string.h>

void *
memccpy(void *restrict s1, const void *restrict s2, int c, size_t n);

void *
memchr(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 *
memmem(const void *l, size_t l_len, const void *s, size_t s_len);

void *
memmove(void *s1, const void *s2, size_t n);

void *
memrchr(void *s, int c, size_t n);

void *
memset(void *s, int c, size_t 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.

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 memrchr() function behaves similarly to the memchr() function, except
that the memory area is searched in reverse from the last byte.

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 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. In such cases, use memmove() instead.

The memmem() function searches for the s_len long byte pattern s in the
memory region starting at l for l_len bytes. If a match is found, a
pointer to the starting location in l is returned. If no match is found,
l_len is zero, s_len is zero, or l_len is less than s_len then a NULL
pointer is return.

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 overlap.

INTERFACE STABILITY

Committed

MT-LEVEL
MT-Safe

NOTES