All of the routines described examine Tcl_UniChars and return a boolean value. A non-zero return value means that the character does belong to the character class associated with the called routine. The rest of this document just describes the character classes associated with the various routines.
Note: A Tcl_UniChar is a Unicode character represented as an unsigned, fixed-size quantity.
Tcl_UniCharIsAlnum tests if the character is an alphanumeric Unicode character.
Tcl_UniCharIsAlpha tests if the character is an alphabetic Unicode character.
Tcl_UniCharIsControl tests if the character is a Unicode control character.
Tcl_UniCharIsDigit tests if the character is a numeric Unicode character.
Tcl_UniCharIsGraph tests if the character is any Unicode print character except space.
Tcl_UniCharIsLower tests if the character is a lowercase Unicode character.
Tcl_UniCharIsPrint tests if the character is a Unicode print character.
Tcl_UniCharIsPunct tests if the character is a Unicode punctuation character.
Tcl_UniCharIsSpace tests if the character is a whitespace Unicode character.
Tcl_UniCharIsUpper tests if the character is an uppercase Unicode character.
Tcl_UniCharIsWordChar tests if the character is alphanumeric or a connector punctuation mark.