memcpy() -- String Function (libc)

Copy one region of memory into another
#include <string.h>
char *memcpy(region1, region2, n)
vaddr_t region1;
vaddr_t region2;
unsigned int n;

memcpy() copies n characters from region2 into region1. Unlike the routines
strcpy()  and  strncpy(),  memcpy()  copies  from  one region  to  another.
Therefore, it will not halt automatically when it encounters NUL.

memcpy() returns region1.

Example

The following example copies a structure and displays it.

#include <string.h>
#include <stdio.h>

struct stuff {
    int a, b, c;
} x, y;

main()
{
    x.a = 1;
    /* this would stop strcpy or strncpy. */
    x.b = 0;
    x.c = 3;

    /* y = x; would do the same */
    memcpy(&y, &x, sizeof(y));
    printf("a =%d, b =%d, c =%d\n", y.a, y.b, y.c);
    return(EXIT_SUCCESS);
}

See Also

libc,
strcpy(),
string.h
ANSI Standard, §7.11.2.1

Notes

If  region1 and  region2 overlap,  the behavior  of memcpy()  is undefined.
region1 should  point to enough  reserved memory to  hold n bytes  of data;
otherwise, code or data will be overwritten.

© 2012 by Stephen A. Ness