/in/foo.cc: In function 'int main()':
/in/foo.cc:10:10: warning: unused variable 'sum' [-Wunused-variable]
  int T,n,sum=0,W1;
          ^~~
/tmp/cc3a1pIn.o: In function `main':
foo.cc:(.text.startup+0x95): relocation truncated to fit: R_X86_64_PC32 against symbol `w' defined in .bss section in /tmp/cc3a1pIn.o
foo.cc:(.text.startup+0x9c): relocation truncated to fit: R_X86_64_PC32 against symbol `v' defined in .bss section in /tmp/cc3a1pIn.o
/tmp/cc3a1pIn.o: In function `_GLOBAL__sub_I_v':
foo.cc:(.text.startup+0x273): relocation truncated to fit: R_X86_64_PC32 against `.bss'
foo.cc:(.text.startup+0x291): relocation truncated to fit: R_X86_64_PC32 against `.bss'
collect2: error: ld returned 1 exit status