Solaris Studio is generating the most puzzling of error messages.
158 char* inbufptr = buffer;
159 char* outbufptr = outbuf;
160
161 const char** inbufptrpos = &inbufptr;
And the error message is:
line 161: Error: Cannot use char** to initialize const char**.
Why should it be a problem to add constness? I am stuck, please help me out...
memory: [m y _ c h a r _ a r r a y | inbufptr | inbufptr_pos]
^ ^
| (1) | (2)
inbufptr inbufptrpos
The pointer char* inbufptr points to the beginning of the array, and does not promise to keep anything constant.
Now if I now have a pointer char const **inbufptr_pos this type promises not the change the contents of the array, but I can still change where the pointer points to. If I do that I have not changed the array and I don't see a problem with that.
This is an age-old problem, whereby intuitively you think you can "add constness", but in fact adding constness indirectly violates const-correctness.
The standard itself even has an example of it to help set people back on the correct path:
#include <cassert>
int main() {
char* p = 0;
//char const** a = &p; // not allowed, but let's pretend it is
char const** a = (char const**)&p; // instead force the cast to compile
char const* orig = "original";
*a = orig; // type of *a is char const*, which is the type of orig, this is allowed
assert(p == orig); // oops! char* points to a char const*
}