cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration wchar/getwchar.c -o wchar/getwchar -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv
wchar/getwchar.c: In function ‘main’:
wchar/getwchar.c:15:14: error: implicit declaration of function ‘fputwc’; did you mean ‘fputc’? [-Wimplicit-function-declaration]
   15 |         if ( fputwc(L'x', stdout) == WEOF )
      |              ^~~~~~
      |              fputc
wchar/getwchar.c:15:35: warning: comparison of integer expressions of different signedness: ‘int’ and ‘unsigned int’ [-Wsign-compare]
   15 |         if ( fputwc(L'x', stdout) == WEOF )
      |                                   ^~
wchar/getwchar.c:19:20: error: implicit declaration of function ‘getwchar’; did you mean ‘getchar’? [-Wimplicit-function-declaration]
   19 |         wint_t c = getwchar();
      |                    ^~~~~~~~
      |                    getchar