On Thu, Oct 09, 2014 at 01:54:57PM +0800, Rongqing Li wrote: > The attachment is a piece of C code. > When compile it with -O2 option, a segfault occurs: > > strncpy(new, old, cp-old);
It is a bug of course, but in the testcase. Calling strncpy with NULL second argument, even when the size is 0, is undefined behavior. See http://gcc.gnu.org/gcc-4.9/porting_to.html
