cc -O2 -pthread  -Wall -Wextra -Werror=implicit-function-declaration locale/uselocale.c -o locale/uselocale -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread -lrt  -lintl -lcrypt
locale/uselocale.c: In function 'main':
locale/uselocale.c:12:24: error: implicit declaration of function 'uselocale'; did you mean 'setlocale'? [-Werror=implicit-function-declaration]
   12 |  locale_t old_locale = uselocale(locale);
      |                        ^~~~~~~~~
      |                        setlocale
locale/uselocale.c:12:24: warning: initialization of 'locale_t' {aka 'struct _locale *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
locale/uselocale.c:15:13: warning: assignment to 'locale_t' {aka 'struct _locale *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
   15 |  old_locale = uselocale((locale_t) 0);
      |             ^
cc1: some warnings being treated as errors