HEADS UP: getenv() and family API change

[Andrey Chernov]

On Wed, Jul 11, 2007 at 12:57:52AM +0200, Erik Trulsson wrote:
> Not the pointer, but the string it points to can be put into read-only
> memory.
> 
> Example:
> 
> static char *s = "PATH=/bin";
> static char *t = "PATH=/bin";
> 
> 
> Here both 's', and 't' can point into read-only memory where the string
> "PATH=/bin" has been placed.  Not only that, they may point to the same
> place, i.e. there need only be one copy of the string "PATH=/bin" in
> the program (but there may be two distinct copies if the compiler does not
> coalesce identical string constants.)
>   
> 
> If on the other hand you use 
> 
> static char s[] = "PATH=/bin";
> static char t[] = "PATH=/bin";
> 
> 
> Then 's' and 't' are no longer pointers to a string constant, but arrays
> that are initialized with the string "PATH=/bin".  These arrays are
> modifiable and distinct - i.e. there will be (at least) two copies of the
> string "PATH=/bin" in memory.

Yes, I agree. Moreover, currently gcc 4.2.0 coalesce "char *" pointed to 
identical string constants and move them to .rodata, so s[] way is better.

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