wcstok(3) code sample

["Stefan Kanthak" <stefan.kanthak@xxxxxxxx>]

Hi,

the examples section of wcstok(3) shows the following code
which exhibits undefined behaviour and typically segfaults:

<https://man7.org/linux/man-pages/man3/wcstok.3.html#EXAMPLES>

|  wchar_t *wcs = ...;
|  wchar_t *token;
|  wchar_t *state;
|  for (token = wcstok(wcs, " \t\n", &state);
|       token != NULL;
|       token = wcstok(NULL, " \t\n", &state)) {
|       ...
|  }

The string literal pointed to by wcs is read-only, and an
attempt to modify a string literal results in undefined
behaviour; wcstok() but writes NULs into its input string.

FIX: replace the first line with either

|  wchar_t *wcs = strdup(...);

     or

|  wchar_t wcs[] = ...;

regards
Stefan