cc -O2 -pipe  -pthread  -Wall -Wextra -Werror -Wno-error=deprecated -Wno-error=deprecated-declarations wchar/vswscanf.c -o wchar/vswscanf -D_POSIX_C_SOURCE=202405L  -lm -lpthread 
wchar/vswscanf.c:5:62: error: type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int [-Werror,-Wimplicit-int]
int (*foo)(const wchar_t *restrict, const wchar_t *restrict, va_list) = vswscanf;
                                                             ^
                                                             int
wchar/vswscanf.c:5:7: error: incompatible function pointer types initializing 'int (*)(const wchar_t *restrict, const wchar_t *restrict, int)' (aka 'int (*)(const int *restrict, const int *restrict, int)') with an expression of type 'int (const wchar_t *restrict, const wchar_t *restrict, struct __va_list_tag *)' (aka 'int (const int *restrict, const int *restrict, struct __va_list_tag *)') [-Werror,-Wincompatible-function-pointer-types]
int (*foo)(const wchar_t *restrict, const wchar_t *restrict, va_list) = vswscanf;
      ^                                                                 ~~~~~~~~
2 errors generated.