cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration wchar/fgetwc.c -o wchar/fgetwc -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv
wchar/fgetwc.c: In function ‘main’:
wchar/fgetwc.c:13:14: error: implicit declaration of function ‘fputwc’; did you mean ‘fputc’? [-Wimplicit-function-declaration]
   13 |         if ( fputwc(c, fp) == WEOF )
      |              ^~~~~~
      |              fputc
wchar/fgetwc.c:13:28: warning: comparison of integer expressions of different signedness: ‘int’ and ‘unsigned int’ [-Wsign-compare]
   13 |         if ( fputwc(c, fp) == WEOF )
      |                            ^~
wchar/fgetwc.c:19:20: error: implicit declaration of function ‘fgetwc’; did you mean ‘fgetc’? [-Wimplicit-function-declaration]
   19 |         wint_t x = fgetwc(fp);
      |                    ^~~~~~
      |                    fgetc