cc -pthread -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations ctype/isxdigit_l.c -o ctype/isxdigit_l -D_POSIX_C_SOURCE=202405L -lm -lpthread -liconv ctype/isxdigit_l.c:5:17: error: type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int [-Wimplicit-int] 5 | int (*foo)(int, locale_t) = isxdigit_l; | ^ | int ctype/isxdigit_l.c:5:29: error: use of undeclared identifier 'isxdigit_l'; did you mean 'isxdigit'? 5 | int (*foo)(int, locale_t) = isxdigit_l; | ^~~~~~~~~~ | isxdigit /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/_ctype.h:282:1: note: 'isxdigit' declared here 282 | isxdigit(int _c) | ^ ctype/isxdigit_l.c:5:7: error: incompatible function pointer types initializing 'int (*)(int, int)' with an expression of type 'int (int)' [-Wincompatible-function-pointer-types] 5 | int (*foo)(int, locale_t) = isxdigit_l; | ^ ~~~~~~~~~~ 3 errors generated.