Bug in std::string::compare(const char*,size_t, size_t)

[Dominik Strasser]

There is a bug in the above function in gcc-2.95.1 (C++ lib)
It can be easily reproduced by the code below:

#include <string>
#include <iostream>

using namespace std;

int main()
{
        string a = "Kuckuck";

        if(a.compare("Kuck", 0, 4)==0)
                cout << "OK";
        else
                cout << "NOK";
        cout << endl;
        if(a.compare(string("Kuck"), 0, 4)==0)
                cout << "OK";
        else
                cout << "NOK";
        cout << endl;
        return 0;
}
The output is:
NOK
OK.

The following fix corrects the behavior:
*** /usr/local/include/g++-3/std/bastring.cc    Mon Oct 25 12:23:04 1999
--- ./bastring.cc       Mon Oct 25 12:20:54 1999
***************
*** 423,428 ****
--- 423,430 ----
    int r = traits::compare (data () + pos, s, rlen);
    if (r != 0)
      return r;
+   if (rlen == n)
+     return 0;
    return (length () - pos) - n;
  }

Regards

Dominik

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