cc -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations math/sqrtl.c -o math/sqrtl -D_POSIX_C_SOURCE=202405L -lm -lpthread -lrt -lintl -liconv math/sqrtl.c:5:35: error: ‘sqrtl’ undeclared here (not in a function); did you mean ‘sqrtf’? 5 | long double (*foo)(long double) = sqrtl; | ^~~~~ | sqrtf