NOMBRE¶

memcpy - copiar area de memoria

BIBLIOTECA¶

Biblioteca Estándar C (libc, -lc)

SINOPSIS¶

#include <string.h>

void *memcpy(void dest[restrict .n], const void src[restrict .n],
             size_t n);

DESCRIPCIÓN¶

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.

VALOR DEVUELTO¶

La funcion memcpy() devuelve un puntero a dest.

ATRIBUTOS¶

Para obtener una explicación de los términos usados en esta sección, véase attributes(7).

ESTÁNDARES¶

C11, POSIX.1-2008.

HISTORIAL¶

POSIX.1-2001, C89, SVr4, 4.3BSD.

CAVEATS¶

Failure to observe the requirement that the memory areas do not overlap has been the source of significant bugs. (POSIX and the C standards 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 implementation, 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 memcpy() implementation that safely handles the overlapping buffers case (by providing an "older" memcpy() implementation that was aliased to memmove(3)).

VÉASE TAMBIÉN¶

bcopy(3), bstring(3), memccpy(3), memmove(3), mempcpy(3), strcpy(3), strncpy(3), wmemcpy(3)

TRADUCCIÓN¶

La traducción al español de esta página del manual fue creada por Vicente Pastor Gómez <vpastorg@santandersupernet.com> y Juan Piernas <piernas@ditec.um.es>

Esta traducción es documentación libre; lea la GNU General Public License Version 3 o posterior con respecto a las condiciones de copyright. No existe NINGUNA RESPONSABILIDAD.

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