Re: Configtool segfaults

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Re: Configtool segfaults

Martin Laabs
Hello,

  I compiled the configtool on my amd64 system (freebsd). After changing some
  int* casts to intptr_t compiling the configtool worked. (Any interests in
  the diff?)
  However - starting the configtool out of a long directory lead to a
  segfault. I traced down the problem to the String::vFormat function

void String::vFormat(LPCTSTR  pszFormat, va_list marker)
{
   for(int nLength=100;nLength;) {
     TCHAR *buf=new TCHAR[1+nLength];
     int n=_vsntprintf(buf, nLength, pszFormat, marker );
     if(-1==n){
       nLength*=2;  // NT behavior
     } else if (n<nLength){
       string::operator=(buf);
       nLength=0;   // trigger exit from loop
     } else {
       nLength=n+1; // UNIX behavior generally, or NT behavior when buffer
size exactly matches required length
     }
     delete [] buf;
   }
}

When the for-loop runs the second time (which occurs when the output string
is longer that 100 chars) the _vsntprintf function is called a second time.
This is not allowed because the va_list argument marker has  already
consumed during the first call.

Anyway - the coding style of this function seems to be somewhat strange.
Why using the "nLength=0;   // trigger exit from loop" instead of calling
exit? However - I'm not very familiar with c++ so it might be the better
way to exit that loop.

Greetings,
  Martin Laabs