/tmp/ccRhElwo.o: In function `main':
foo.cc:(.text.startup+0x3f): relocation truncated to fit: R_X86_64_PC32 against symbol `buc' defined in .bss section in /tmp/ccRhElwo.o
foo.cc:(.text.startup+0x4e): relocation truncated to fit: R_X86_64_PC32 against symbol `a' defined in .bss section in /tmp/ccRhElwo.o
foo.cc:(.text.startup+0x55): relocation truncated to fit: R_X86_64_PC32 against symbol `sum' defined in .bss section in /tmp/ccRhElwo.o
foo.cc:(.text.startup+0x5c): relocation truncated to fit: R_X86_64_PC32 against symbol `sum' defined in .bss section in /tmp/ccRhElwo.o
foo.cc:(.text.startup+0x63): relocation truncated to fit: R_X86_64_PC32 against symbol `buc' defined in .bss section in /tmp/ccRhElwo.o
foo.cc:(.text.startup+0xdd): relocation truncated to fit: R_X86_64_PC32 against symbol `buc' defined in .bss section in /tmp/ccRhElwo.o
foo.cc:(.text.startup+0x139): relocation truncated to fit: R_X86_64_PC32 against symbol `buc' defined in .bss section in /tmp/ccRhElwo.o
foo.cc:(.text.startup+0x150): relocation truncated to fit: R_X86_64_PC32 against symbol `sum' defined in .bss section in /tmp/ccRhElwo.o
/tmp/ccRhElwo.o: In function `_GLOBAL__sub_I_a':
foo.cc:(.text.startup+0x193): relocation truncated to fit: R_X86_64_PC32 against `.bss'
foo.cc:(.text.startup+0x1b1): relocation truncated to fit: R_X86_64_PC32 against `.bss'
collect2: error: ld returned 1 exit status