Determines whether a character is alphabetic (i.e. a letter).
Unlike the standard C library isalpha() function, this only
recognizes standard ASCII letters and ignores the locale, returning
FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a char, not an int,
so don't call it on EOF but no need to cast to guchar before passing a
possibly non-ASCII character in.
Determines whether a character is alphabetic (i.e. a letter). Unlike the standard C library isalpha() function, this only recognizes standard ASCII letters and ignores the locale, returning FALSE for all non-ASCII characters. Also unlike the standard library function, this takes a char, not an int, so don't call it on EOF but no need to cast to guchar before passing a possibly non-ASCII character in.