cc -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations wctype/iswcntrl_l.c -o wctype/iswcntrl_l -D_POSIX_C_SOURCE=202405L -lm -lpthread -liconv wctype/iswcntrl_l.c:5:20: error: type specifier missing, defaults to 'int' [-Werror,-Wimplicit-int] int (*foo)(wint_t, locale_t) = iswcntrl_l; ^ wctype/iswcntrl_l.c:5:32: error: use of undeclared identifier 'iswcntrl_l'; did you mean 'iswcntrl'? int (*foo)(wint_t, locale_t) = iswcntrl_l; ^~~~~~~~~~ iswcntrl /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/_wctype.h:63:1: note: 'iswcntrl' declared here iswcntrl(wint_t _wc) ^ wctype/iswcntrl_l.c:5:7: error: incompatible function pointer types initializing 'int (*)(wint_t, int)' (aka 'int (*)(int, int)') with an expression of type 'int (wint_t)' (aka 'int (int)') [-Werror,-Wincompatible-function-pointer-types] int (*foo)(wint_t, locale_t) = iswcntrl_l; ^ ~~~~~~~~~~ 3 errors generated.