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memcpy(3) [debian man page]

MEMCPY(3)						     Linux Programmer's Manual							 MEMCPY(3)

NAME
memcpy - copy memory area SYNOPSIS
#include <string.h> void *memcpy(void *dest, const void *src, size_t n); DESCRIPTION
The memcpy() function copies n bytes from memory area src to memory area dest. The memory areas must not overlap. Use memmove(3) if the memory areas do overlap. RETURN VALUE
The memcpy() function returns a pointer to dest. CONFORMING TO
SVr4, 4.3BSD, C89, C99, POSIX.1-2001. SEE ALSO
bcopy(3), memccpy(3), memmove(3), mempcpy(3), strcpy(3), strncpy(3), wmemcpy(3) COLOPHON
This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. 2010-11-15 MEMCPY(3)

Check Out this Related Man Page

MEMCPY(3)						     Linux Programmer's Manual							 MEMCPY(3)

NAME
memcpy - copy memory area SYNOPSIS
#include <string.h> void *memcpy(void *dest, const void *src, size_t n); DESCRIPTION
The memcpy() function copies n bytes from memory area src to memory area dest. The memory areas must not overlap. Use memmove(3) if the memory areas do overlap. RETURN VALUE
The memcpy() function returns a pointer to dest. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +----------+---------------+---------+ |Interface | Attribute | Value | +----------+---------------+---------+ |memcpy() | Thread safety | MT-Safe | +----------+---------------+---------+ CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD. NOTES
Failure to observe the requirement that the memory areas do not overlap has been the source of significant bugs. (POSIX and the C stan- dards are explicit that employing memcpy() with overlapping areas produces undefined behavior.) Most notably, in glibc 2.13 a performance optimization of memcpy() on some platforms (including x86-64) included changing the order in which bytes were copied from src to dest. This change revealed breakages in a number of applications that performed copying with overlapping areas. Under the previous implementa- tion, the order in which the bytes were copied had fortuitously hidden the bug, which was revealed when the copying order was reversed. In glibc 2.14, a versioned symbol was added so that old binaries (i.e., those linked against glibc versions earlier than 2.14) employed a mem- cpy() implementation that safely handles the overlapping buffers case (by providing an "older" memcpy() implementation that was aliased to memmove(3)). SEE ALSO
bcopy(3), bstring(3), memccpy(3), memmove(3), mempcpy(3), strcpy(3), strncpy(3), wmemcpy(3) COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. 2017-09-15 MEMCPY(3)

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