On 10/13/14 21:18, Chen Gang wrote: > On 10/13/14 18:53, Jason Merrill wrote: >> On 10/12/2014 10:32 AM, Chen Gang wrote: >>> [root@localhost qemu_cc]# cat test.cc >>> const char n() { return 1; } >>> const char c = n(); >>> [root@localhost qemu_cc]# /usr/local/bin/g++ -Wall -O0 -c -o test.o >>> test.cc >>> [root@localhost qemu_cc]# /usr/local/bin/g++ -Wall -O2 -c -o test.o >>> test.cc >>> test.cc:2:12: warning: 'c' defined but not used [-Wunused-variable] >>> const char c = n(); >>> ^ >> >> The warning is correct (and new). Please submit bug reports via the >> website; see https://gcc.gnu.org/bugs/ >>
Thank Jason Merrill, again. At present, I have got enough confirmation from you and other members (excuse me, I am not quite familiar with C++, for me, it is a complex language, so need several members confirmation). And if no additional reply within this week, I shall submit bug reports, and try to fix it within this month (although I am really not quite sure). I am not quite familiar with C++, so if any members worry about me: feel that I am not quite suitable to report bug and fix it, please let me know within this week. Thanks. > > OK, thanks. After finish this consult, I shall report bugs, and shall > try to fix it (I got it from Qemu which in my current focus border). > Hope I can finish within this month. > > And one another consult: if the constant variable is defined in header > file, and never be used, need our g++ still report warning about > [-Wunused-variable] too (for me, I guess, not)? > > > Thanks. > -- Chen Gang Open, share, and attitude like air, water, and life which God blessed