Syntax

#include <wctype.h>
wint_t towlower(wint_t wc);
wint_t towupper(wint_t wc);

towlower converts the uppercase letter wc to the corresponding lowercase letter.

towupper converts the lowercase letter wc to the corresponding uppercase letter.

The character mapping is determined by the LC_CTYPE category of current locale.

Both functions return the converted character. If the wide character wc does not have a corresponding lowercase or uppercase character, the functions return wc unchanged.

This example uses towlower and towupper to convert characters between 0 and 0x7f.

#include <wchar.h>
#include <stdio.h>

int main(void)
{
   wint_t w_ch;

   for (w_ch = 0; w_ch <= 0x7f; w_ch++) {
      printf ("towupper : %#04x %#04x, ", w_ch, towupper(w_ch));
      printf ("towlower : %#04x %#04x\n", w_ch, towlower(w_ch));
   }
   return 0;

   /****************************************************************************
      The output should be similar to :
      .
      :
      towupper : 0x41 0x41, towlower : 0x41 0x61
      towupper : 0x42 0x42, towlower : 0x42 0x62
      towupper : 0x43 0x43, towlower : 0x43 0x63
      towupper : 0x44 0x44, towlower : 0x44 0x64
      towupper : 0x45 0x45, towlower : 0x45 0x65
      .
      :
      towupper : 0x61 0x41, towlower : 0x61 0x61
      towupper : 0x62 0x42, towlower : 0x62 0x62
      towupper : 0x63 0x43, towlower : 0x63 0x63
      towupper : 0x64 0x44, towlower : 0x64 0x64
      towupper : 0x65 0x45, towlower : 0x65 0x65
      :
   ****************************************************************************/
}

• tolower - toupper
  
• toascii - _tolower - _toupper

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