On Mon, 10 Aug 2015, Xin Li wrote:
On 8/10/15 22:51, Ed Schouten wrote:
2015-08-11 1:20 GMT+02:00 Xin Li <delp...@delphij.net>:
Do you have a better solution for this? No, this is not ideal
but I didn't find a better alternative (or maybe I have missed
something obvious?)
I think with the current POSIX definition of the interface, we
have only two options: either strdup() or cast away const (I'd
rather hide this kind of uglyness in the library), no?
Casting const away should be all right in this case.
It is the Standard way.
Committed as r286617, please let me know if you want other
changes, etc.
Perhaps we should convert the tree over time to use __DECONST instead
then?
Gak!. I use rmrf on code with __DECONST in it.
The misimplementation of __DECONST only "works" because -Wcast-qual is
too broken to detect removal of qualifiers by casting a pointer to an
integer. Casting a pointer to an integer is much less safe than
casting away only a qualifer for a pointer, but both are Standard,
so they work unless the compiler is directed to be nonstandard using
-Wcast-qual -Werror.
Compilers should know about the language defects that make it impossible
to declare functions like execv() with the correct number of const's
and turn off -Wcast-qual warnings for these functions.
strchr() is another function that needs special. It can take a pointer
const char and return a related pointer with the const qualifier removed
(subtract an offset to get the original pointer with its const qualifier
removed). The warning about this from -Wcast-qual is not yet killed
using __DECONST() because libc is still compiled with a low WARNS.
The implementation uses a cast in the Standard way. Only the
implementation would be affected by -Wcast-qual. But a flag like
-Wcast-qual should direct the compiler to warn about removal of casts
by abusing strchr() too.
Bruce
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