MEMORY(10.2)

NAME

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

SYNOPSIS

void∗memccpy(void ∗s1, void ∗s2, int c, long n)

void∗memchr(void ∗s, int c, long n)

intmemcmp(void ∗s1, void ∗s2, long n)

void∗memcpy(void ∗s1, void ∗s2, long n)

void∗memmove(void ∗s1, void ∗s2, long n)

void∗memset(void ∗s, int c, long n)

DESCRIPTION

These functions operate efficiently on memory areas (arrays of bytes bounded by a count, not terminated by a zero byte). They do not check for the overflow of any receiving memory area.

Memccpy copies bytes from memory area s2 into s1, stopping after the first occurrence of byte c 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 zero if c was not found in the first n bytes of s2.

Memchr returns a pointer to the first occurrence of byte c in the first n bytes of memory area s, or zero if c does not occur.

Memcmp compares its arguments, looking at the first n bytes 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. The comparison is bytewise unsigned.

Memmove copies n bytes from memory area s2 to s1. It returns s1. It is guaranteed to work if s1 and s2 overlap.

In the Inferno kernel memcpy is equivalent to memmove. (In ANSI C, by contrast, memcpy does not account for overlapping memory regions.)

Memset sets the first n bytes in memory area s to the value of the least significant byte of c. It returns s.

DIAGNOSTICS

If memcpy and memmove are handed negative counts, they abort.

SOURCE

/kern/mem∗.c
/kern/mem∗-objtype.s

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