https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105950
--- Comment #2 from John Kanapes <jkanapes at yahoo dot com> --- Hi, The missing info, gcc -v -save-temps is provided as an attachment. Of the flags, Wextra, -fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations did nothing. -fsanitize=undefined creates the following output for main: usr/bin/ld: capture.o: in function `main.cold': capture.c:(.text.unlikely+0x112): undefined reference to `__ubsan_handle_load_invalid_value' /usr/bin/ld: capture.c:(.text.unlikely+0x13a): undefined reference to `__ubsan_handle_nonnull_arg' /usr/bin/ld: capture.c:(.text.unlikely+0x16b): undefined reference to `__ubsan_handle_nonnull_arg' /usr/bin/ld: capture.c:(.text.unlikely+0x19c): undefined reference to `__ubsan_handle_nonnull_arg' /usr/bin/ld: capture.c:(.text.unlikely+0x1cd): undefined reference to `__ubsan_handle_nonnull_arg' /usr/bin/ld: capture.c:(.text.unlikely+0x1f6): undefined reference to `__ubsan_handle_nonnull_arg' /usr/bin/ld: capture.o:capture.c:(.text.unlikely+0x21f): more undefined references to `__ubsan_handle_nonnull_arg' follow /usr/bin/ld: capture.o: in function `main.cold': capture.c:(.text.unlikely+0x35e): undefined reference to `__ubsan_handle_load_invalid_value' /usr/bin/ld: capture.c:(.text.unlikely+0x381): undefined reference to `__ubsan_handle_load_invalid_value' /usr/bin/ld: capture.c:(.text.unlikely+0x3a1): undefined reference to `__ubsan_handle_nonnull_arg' /usr/bin/ld: capture.c:(.text.unlikely+0x3c1): undefined reference to `__ubsan_handle_nonnull_arg' /usr/bin/ld: capture.c:(.text.unlikely+0x3e1): undefined reference to `__ubsan_handle_nonnull_arg' /usr/bin/ld: capture.c:(.text.unlikely+0x409): undefined reference to `__ubsan_handle_load_invalid_value' /usr/bin/ld: capture.c:(.text.unlikely+0x42a): undefined reference to `__ubsan_handle_load_invalid_value' /usr/bin/ld: capture.o: in function `main': capture.c:(.text.startup+0xa2d): undefined reference to `__ubsan_handle_pointer_overflow' /usr/bin/ld: capture.c:(.text.startup+0x1042): undefined reference to `__ubsan_handle_sub_overflow' /usr/bin/ld: capture.c:(.text.startup+0x1053): undefined reference to `__ubsan_handle_out_of_bounds' /usr/bin/ld: capture.c:(.text.startup+0x1067): undefined reference to `__ubsan_handle_pointer_overflow' /usr/bin/ld: capture.c:(.text.startup+0x107e): undefined reference to `__ubsan_handle_pointer_overflow' /usr/bin/ld: capture.c:(.text.startup+0x1092): undefined reference to `__ubsan_handle_type_mismatch_v1' collect2: error: ld returned 1 exit status
