memory(2) [plan9 man page]

MEMORY(2)							System Calls Manual							 MEMORY(2)

NAME

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

SYNOPSIS

       #include <u.h>
       #include <libc.h>

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

       void* memchr(void *s, int c, long n)

       int   memcmp(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.

       Memcpy copies n bytes from memory area s2 to s1.  It returns s1.

       Memmove works like memcpy, except that it is guaranteed to work if s1 and s2 overlap.

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

SOURCE

       All  these  routines have portable C implementations in /sys/src/libc/port.  Most also have machine-dependent assembly language implementa-
       tions in /sys/src/libc/$objtype.

SEE ALSO

       strcat(2)

BUGS

       ANSI C does not require memcpy to handle overlapping source and destination; on Plan 9, it does, so memmove and memcpy behave identically.

       If memcpy and memmove are handed a negative count, they abort.

																	 MEMORY(2)

memory(3C)						   Standard C Library Functions 						memory(3C)

NAME

       memory, memccpy, memchr, memcmp, memcpy, memmove, memset - 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);

   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 (arrays of bytes bounded by a count, not terminated by a null charac-
       ter). 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  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 lexicographically 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.

       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.

USAGE

       Using memcpy() might be faster than using memmove() if the application knows that the objects being copied do not overlap.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Stable			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+
       |Standard		     |See standards(5). 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       string(3C), attributes(5), standards(5)

NOTES

       Overlap	between objects being copied can arise even when their (virtual) 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.

SunOS 5.11							    4 Feb 2009								memory(3C)