C Standard Library

C <wctype.h> - iswlower() Function

The C <wctype.h> iswlower() function is used to check if the given wide character is a lowercase letter. In the default "C" locale, the following are the lowercase letters: abcdefghijklmnopqrstuvwxyz. Other locales may consider a different selection of wide characters as lowercase letters.


int iswlower ( wint_t ch );               


ch Specify the wide character to be checked, casted to an wint_t, or WEOF.

Return Value

Returns non-zero value (i.e, true) if ch is a lowercase letter, else returns zero (i.e, false).


The example below shows the usage of iswlower() function.

#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
int main (){
  wchar_t str[50] = L"99HEllo";

  //counting the number of lowercase
  //wide characters in str
  int i = 0, count = 0;
  while(str[i]) {

  //displaying the output
  printf("%ls contains %d lowercase letters.", str, count);  
  return 0;

The output of the above code will be:

99HEllo contains 3 lowercase letters.

❮ C <wctype.h> Library