Read uninitialized (rui)

Question

Hello,
I currenlty try to clean my code of rui/wui etc...
First thing I am wondering of: is the rui output in the sunstudio debuger always reliable ?
Or could it be theat I some times does not check that a variable has being initialized indirectly ?
currently I receive this complaint :
Read from uninitialized (rui) on thread 1:
Attempting to read 3 bytes at address 0xffbee799
which is 289 bytes above the current stack pointer
Location of error: IBAG_iniparser.cpp, line 0, std::istreambuf_iterator<char,std::char_traits<char> >::istreambuf_iterator()
typedef std::istreambuf_iterator<char> IsbIt;
   class StreamToString
        IsbIt p;
        IsbIt end;
        public:
           StreamToString(std::istream &is ) : p(is), end(IsbIt()), iss(is)   // the rui comes out here. My guess is end(IsbIt()) causes it.
The caller passes an ifsream to the overloaded constructor.
since the rui comes out of istreambuf_iterator<char, std::char_traits<char> >::istreambuf_iterator(0xffbee954, 0xffbee794, 0xffbee9e8, 0x78, 0x0, 0x1)  i cannot step onto this function.
Any Idea why this could be a rui ?
regards
fagery

Answer 1

In general, RUIs can be false positives, as explained in the dbx documentation and dbx help. For example, you can get an RUI when copying padding bytes in a struct:
struct S {
char c;
int i;
On sparc, struct S will have 3 uninitialized bytes between members 'c' and 'i'. A struct copy will copy these bytes, leading to a false RUI report. We have been taking steps to reduce the number of false RUIs via additional compiler options.
But reading from above the stack pointer is not a false positive.
In this case, the problem appears to be due to a bug in either the library or in dbx. I was able to duplicate your problem using the latest patched Studio 11, but not with the Studio 12 Early Access compiler. I was not able to locate a specific bug report, however. I'll do some more checking, and let you know if I find an associated bug report.