> Could someone tell me the `official' story here :

 > I am updating something for a microcontroller-based
 > application, and my cross-compiler is a supposedly ANSI C
 > platform. However, the existing source contains numerous
 > things like this :

 > char s[256];
 > ....
 > sprintf((char *)&s,"password %s is incorrect (attempt
-1.1%d)",&s,i);
 > ....

 > This particular compiler generates object code which is something like :

 > char s[256],*s2;
 > ...
 > s2=malloc[256];
 > sprintf(s2,"password %s is incorrect (attempt -1.1%d)",&s,i);
 > strcpy((char *)&s,s2);
 > free(s2);
 > ...

 > The sprintf() function apparently contains a small buffer
 > string inside it to cope with a self-referencing argument
 > list. Is this standard C ? I think not.. but I want to be
 > sure.


The behaviour of what is called "copying between overlapping
objects" is "undefined" under ISO-C. It might work or it
might not, but I wouldn't rely on it.

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