string encoding

Gnuplot's built-in string manipulation functions are sensitive to utf-8 encoding (see set encoding). For example

 set encoding utf8
 utf8string = "αβγ"
 strlen(utf8string) returns 3 (number of characters, not number of bytes)
 utf8string[2:2] evaluates to "β"
 strstrt(utf8string,"β") evaluates to 2