cc -pipe -O -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations termios/FF1.c -o termios/FF1 -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lrt -lcrypt termios/FF1.c:8:17: error: 'FF1' undeclared here (not in a function) int const foo = FF1; ^~~