ref: b502a62da2ec6058923db94f87ecc2d29db2fa77
dir: /man/10/memory/
.TH MEMORY 10.2 .SH NAME memccpy, memchr, memcmp, memcpy, memmove, memset \- memory operations .SH SYNOPSIS .ta \w'\fLvoid* 'u .B void* memccpy(void *s1, void *s2, int c, long n) .PP .B void* memchr(void *s, int c, long n) .PP .B int memcmp(void *s1, void *s2, long n) .PP .B void* memcpy(void *s1, void *s2, long n) .PP .B void* memmove(void *s1, void *s2, long n) .PP .B void* memset(void *s, int c, long n) .SH 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. .PP .I Memccpy copies bytes from memory area .I s2 into .IR s1 , stopping after the first occurrence of byte .I c has been copied, or after .I n bytes have been copied, whichever comes first. It returns a pointer to the byte after the copy of .I c in .IR s1 , or zero if .I c was not found in the first .I n bytes of .IR s2 . .PP .I Memchr returns a pointer to the first occurrence of byte .I c in the first .I n bytes of memory area .IR s, or zero if .I c does not occur. .PP .I Memcmp compares its arguments, looking at the first .I n bytes only, and returns an integer less than, equal to, or greater than 0, according as .I s1 is lexicographically less than, equal to, or greater than .IR s2 . The comparison is bytewise unsigned. .PP .I Memmove copies .I n bytes from memory area .I s2 to .IR s1 . It returns .IR s1 . It is guaranteed to work if .I s1 and .IR s2 overlap. .PP In the Inferno kernel .I memcpy is equivalent to .IR memmove . (In ANSI C, by contrast, .I memcpy does not account for overlapping memory regions.) .PP .I Memset sets the first .I n bytes in memory area .I s to the value of the least significant byte of .IR c . It returns .IR s . .SH DIAGNOSTICS If .I memcpy and .I memmove are handed negative counts, they abort. .SH SOURCE .BR /libkern/mem*.c .br .BR /libkern/mem*-\fIobjtype\fP.s .SH SEE ALSO .IR strcat (10.2)