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Full Discussion: shared memory overlapping
Operating Systems Solaris shared memory overlapping Post 302521577 by achenle on Wednesday 11th of May 2011 05:22:25 PM
Old 05-11-2011
How does it crash? And why does this suggest shared memory overlapping?
 

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memory(3)						     Library Functions Manual							 memory(3)

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

Syntax
       #include <string.h>

       void *memccpy (s1, s2, c, n)
       void *s1, *s2;
       int c;
       size_t n;

       void *memchr (s, c, n)
       void *s;
       int c;
       size_t n;

       int memcmp (s1, s2, n)
       void *s1, *s2;
       size_t n;

       void *memcpy (s1, s2, n)
       void *s1, *s2;
       size_t n;

       void *memset (s, c, n)
       void *s;
       int c;
       size_t n;

       void *memmove (s1, s2, n)
       void *s1, *s2;
       size_t n;

Description
       These functions operate efficiently on memory areas (arrays of characters bounded by a count, not terminated by a null character).  They do
       not check for the overflow of any receiving memory area.

       The subroutine copies characters from memory area s2 into s1, stopping after the first occurrence of character c has been copied, or  after
       n  characters  have been copied, whichever comes first.	It returns a pointer to the character after the copy of c in s1, or a NULL pointer
       if c was not found in the first n characters of s2.

       The subroutine returns a pointer to the first occurrence of character c in the first n characters of memory area s, or a NULL pointer if  c
       does not occur.

       The  subroutine compares its arguments, looking at the first n characters 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 subroutine copies n characters from memory area s2 to s1.  It returns s1.

       The subroutine is like , except that if s1 and s2 specify overlapping areas, works as if an intermediate buffer is used.

       The subroutine sets the first n characters in memory area s to the value of character c.  It returns s.

Restrictions
       The subroutine uses native character comparison, which is signed on PDP-11s, unsigned on other machines.

       Character movement is performed differently in different implementations of and Thus overlapping moves, using these subroutines, may  yield
       unpredictable results.

																	 memory(3)
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