public inbox for
 help / color / mirror / Atom feed
* Re: Configtool segfaults
       [not found] <>
@ 2011-10-07 15:06 ` Martin Laabs
  0 siblings, 0 replies; only message in thread
From: Martin Laabs @ 2011-10-07 15:06 UTC (permalink / raw)
  To: eCos Developer List


  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 );
       nLength*=2;  // NT behavior
     } else if (n<nLength){
       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.

  Martin Laabs

^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2011-10-07 15:06 UTC | newest]

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <>
2011-10-07 15:06 ` Configtool segfaults Martin Laabs

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).