The functions wctrans() and towctrans() are also defined in
wctrans_t wctrans(const char *mapping);
wint_t towctrans(wint_t ch, wctrans_t mapping_ob);
tolower
toupper
The following sequence demonstrates wctrans() and towctrans():
#include
#include
int main(void){
wctrans_t x;
x = wctrans("tolower");
wchar_t ch = towctrans(L'W', x);
printf("%c", (char) ch);
}