| Classification functions | |
| iswalnum | Is character alphanumeric? |
| iswalpha | Is character alphabetic? |
| iswblank | Is character blank? |
| iswcntrl | Is character a control? |
| iswctype | Determine character type |
| iswdigit | Is character a decimal digit? |
| iswgraph | Is character a control? |
| iswlower | Is character a lowercase letter? |
| iswprint | Is character printable? |
| iswpunct | Is character punctuation? |
| iswspace | Is character a whitespace character? |
| iswupper | Is character an uppercase letter? |
| iswxdigit | Is character a hexadecimal digit? |
| wctype | Construct character class |
| Conversion functions | |
| towctrans | Translate character |
| towlower | Convert uppercase character to lowercase |
| towupper | Convert lowercase character to uppercase |
| wctrans | Construct character mapping |
| Classification functions (extended) | |
| iswalnum_l | Is character alphanumeric? |
| iswalpha_l | Is character alphabetic? |
| iswblank_l | Is character blank? |
| iswcntrl_l | Is character a control? |
| iswctype_l | Determine character type |
| iswdigit_l | Is character a decimal digit? |
| iswgraph_l | Is character a control? |
| iswlower_l | Is character a lowercase letter? |
| iswprint_l | Is character printable? |
| iswpunct_l | Is character punctuation? |
| iswspace_l | Is character a whitespace character? |
| iswupper_l | Is character an uppercase letter? |
| iswxdigit_l | Is character a hexadecimal digit? |
| Conversion functions (extended) | |
| towctrans_l | Translate character |
| towlower_l | Convert uppercase character to lowercase |
| towupper_l | Convert lowercase character to uppercase |
| wctrans_l | Construct character mapping |