MEMORY(3) — C LIBRARY FUNCTIONS

NAME

memory, memccpy, memchr, memcmp, memcpy, memset − memory operations

SYNOPSIS

#include <memory.h>

char ∗memccpy (s1, s2, c, n)
char ∗s1, ∗s2;
int c, n;

char ∗memchr (s, c, n)
char ∗s;
int c, n;

int memcmp (s1, s2, n)
char ∗s1, ∗s2;
int n;

char ∗memcpy (s1, s2, n)
char ∗s1, ∗s2;
int n;

char ∗memset (s, c, n)
char ∗s;
int c, n;

DESCRIPTION

memset These functions operate as efficiently as possible on memory areas (arrays of characters bounded by a count, not terminated by a null character). They do not check for the overflow of any receiving memory area.

memccpy copies characters from memory area s2 into s1, stopping after the first occurrence of character c has been copied, or after n characters have been copied, whichever comes first. It returns a pointer to the character after the copy of c in s1, or a NULL pointer if c was not found in the first n characters of s2.

memchr returns a pointer to the first occurrence of character c in the first n characters of memory area s, or a NULL pointer if c does not occur.

memcmp compares its arguments, looking at the first n characters only, 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.

memcpy copies n characters from memory area s2 to s1. It returns s1.

memset sets the first n characters in memory area s to the value of character c. It returns s.

NOTE

For user convenience, all these functions are declared in the optional <memory.h> header file.

BUGS

memcmp uses native character comparison, which is signed on some machines and unsigned on other machines. Thus the sign of the value returned when one of the characters has its high-order bit set is implementation-dependent.

Character movement is performed differently in different implementations. Thus overlapping moves may yield surprises.