The arguments to ctype(3) functions need to be EOF or representable as an unsigned char. These replacement functions avoid replicating the checks for valid arguments.
| Function | Description | Links |
|---|---|---|
| mutt_isalnum() | isalnum(3) | |
| mutt_isalpha() | isalpha(3) | |
| mutt_isdigit() | isdigit(3) | |
| mutt_ispunct() | ispunct(3) | |
| mutt_isspace() | isspace(3) | |
| mutt_isxdigit() | isxdigit(3) | |
| mutt_tolower() | tolower(3) | |
| mutt_toupper() | toupper(3) |
