/* Returns true for every standard whitespace character (' ', '\f', '\n', '\r',
'\t', '\v') in the "C" locale. In any other locale, also returns true for a
locale-specific set of characters for which isalnum() is false.
/* Returns true for every standard whitespace character (' ', '\f', '\n', '\r',
'\t', '\v') in the "C" locale. In any other locale, also returns true for a
locale-specific set of characters for which isalnum() is false.