clang -O2 -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations strings/ffsl.c -o strings/ffsl -D_POSIX_C_SOURCE=202405L -lm -lintl strings/ffsl.c:11:20: error: use of undeclared identifier 'ffsl'; did you mean 'ffs'? int (*foo)(long) = ffsl; ^~~~ ffs /usr/include/strings.h:55:6: note: 'ffs' declared here int ffs(int); ^ strings/ffsl.c:11:7: error: incompatible pointer types initializing 'int (*)(long)' with an expression of type 'int (int)' [-Werror,-Wincompatible-pointer-types] int (*foo)(long) = ffsl; ^ ~~~~ 2 errors generated.