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Top Forums Programming Cannot access memory at address 0x8 Post 302212338 by Roman Voznyuk on Monday 7th of July 2008 07:57:05 AM
Old 07-07-2008
Working/not working depends on implementation of kernel.
Basically how particular kernel deals with memory.
Sometimes it might allow you to read whatever your want, or might not.

For example in case of DOS you call is always valid, becuase iterrupts vector area is located in that area.

At the same time it's big security flaw if any procees is allowed to read any piece of memory. It might be a way to easily obtaint passwords, decription keys, etc. That's one of the reasosn, why you have such exception.

Your program is wrong regardless if it's HP-UX or Linux. It does that you didn't intend to do. You must rewrtie in order to avoid defrefencing of tha null-pointer.
 

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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 should 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 3.25 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/. 1993-04-10 MEMCPY(3)
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