Tcl_UniCharIsAlpha (man3)
Tcl_UniCharIsAlnum, Tcl_UniCharIsAlpha, Tcl_UniCharIsControl, Tcl_UniCharIsDigit, Tcl_UniCharIsGraph, Tcl_UniCharIsLower, Tcl_UniCharIsPrint, Tcl_UniCharIsPunct, Tcl_UniCharIsSpace, Tcl_UniCharIsUpper, Tcl_UniCharIsWordChar − routines for classification of Tcl_UniChar characters