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. -- http://ache.pp.ru/Received on Wed Jul 11 2007 - 00:58:23 UTC
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