gcc -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations math/M_SQRT3.c -o math/M_SQRT3 -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lxnet -lsocket -latomic math/M_SQRT3.c:8:21: error: ‘M_SQRT3’ undeclared here (not in a function); did you mean ‘M_SQRT2’? 8 | double const foo = M_SQRT3; | ^~~~~~~ | M_SQRT2